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A261143 - OEIS
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <html> <head> <link rel="stylesheet" href="/styles.css"> <meta name="format-detection" content="telephone=no"> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <meta name=viewport content="width=device-width, initial-scale=1"> <meta name="keywords" content="OEIS,integer sequences,Sloane" /> <title>A261143 - OEIS</title> <link rel="search" type="application/opensearchdescription+xml" title="OEIS" href="/oeis.xml"> <script> var myURL = "\/A261143" function redir() { var host = document.location.hostname; if(host != "oeis.org" && host != "127.0.0.1" && !/^([0-9.]+)$/.test(host) && host != "localhost" && host != "localhost.localdomain") { document.location = "https"+":"+"//"+"oeis"+".org/" + myURL; } } function sf() { if(document.location.pathname == "/" && document.f) document.f.q.focus(); } </script> </head> <body bgcolor=#ffffff onload="redir();sf()"> <div class=loginbar> <div class=login> <a href="/login?redirect=%2fA261143">login</a> </div> </div> <div class=center><div class=top> <center> <div class=donors> The OEIS is supported by <a href="http://oeisf.org/#DONATE">the many generous donors to the OEIS Foundation</a>. </div> <div class=banner> <a href="/"><img class=banner border="0" width="600" src="/banner2021.jpg" alt="A261143 - OEIS"></a> </div> <div class="motdbox"> <div class="motd"> <p>Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).</p> </div> <div class="donate"> <div id="donate-button-container"> <div id="donate-button"></div> <script src="https://www.paypalobjects.com/donate/sdk/donate-sdk.js" charset="UTF-8"></script> <script> PayPal.Donation.Button({ env:'production', hosted_button_id:'SVPGSDDCJ734A', image: { src:'https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif', alt:'Donate with PayPal button', title:'PayPal - The safer, easier way to pay online!', } }).render('#donate-button'); </script> </div> <a href="https://oeisf.org/donate/"> <strong>Other ways to Give</strong> </a> </div> </div> </center> </div></div> <div class=center><div class=pagebody> <div class=searchbarcenter> <form name=f action="/search" method="GET"> <div class=searchbargreet> <div class=searchbar> <div class=searchq> <input class=searchbox maxLength=1024 name=q value="" title="Search Query"> </div> <div class=searchsubmit> <input type=submit value="Search" name=go> </div> <div class=hints> <span class=hints><a href="/hints.html">Hints</a></span> </div> </div> <div class=searchgreet> (Greetings from <a href="/welcome">The On-Line Encyclopedia of Integer Sequences</a>!) </div> </div> </form> </div> <div class=sequence> <div class=space1></div> <div class=line></div> <div class=seqhead> <div class=seqnumname> <div class=seqnum> A261143 </div> <div class=seqname> a(n) = H_n(1,2) where H_n is the n-th hyperoperator. </div> </div> <div class=scorerefs> 3 </div> </div> <div> <div class=seqdatabox> <div class=seqdata>3, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1</div> <div class=seqdatalinks> (<a href="/A261143/list">list</a>; <a href="/A261143/constant">constant</a>; <a href="/A261143/graph">graph</a>; <a href="/search?q=A261143+-id:A261143">refs</a>; <a href="/A261143/listen">listen</a>; <a href="/history?seq=A261143">history</a>; <a href="/search?q=id:A261143&fmt=text">text</a>; <a href="/A261143/internal">internal format</a>) </div> </div> </div> <div class=entry> <div class=section> <div class=sectname>OFFSET</div> <div class=sectbody> <div class=sectline>0,1</div> </div> </div> <div class=section> <div class=sectname>COMMENTS</div> <div class=sectbody> <div class=sectline>See <a href="/A054871" title="a(n) = H_n(3,2) where H_n is the n-th hyperoperator.">A054871</a> for definitions and key links.</div> <div class=sectline>Sequence is also the decimal expansion of 2989/9000.</div> </div> </div> <div class=section> <div class=sectname>LINKS</div> <div class=sectbody> <div class=sectline><a href="/A261143/b261143.txt">Table of n, a(n) for n=0..104.</a></div> <div class=sectline>Dominika Závacká, Cristina Dalfó, and Miquel Angel Fiol, <a href="https://ceur-ws.org/Vol-3792/paper19.pdf">Integer sequences from k-iterated line digraphs</a>, CEUR: Proc. 24th Conf. Info. Tech. - Appl. and Theory (ITAT 2024) Vol 3792, 156-161. See p. 161, Table 2.</div> <div class=sectline><a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1).</div> </div> </div> <div class=section> <div class=sectname>FORMULA</div> <div class=sectbody> <div class=sectline>From <a href="/wiki/User:Elmo_R._Oliveira">Elmo R. Oliveira</a>, Jul 16 2024: (Start)</div> <div class=sectline>G.f.: (3-x^2-x^3)/(1-x).</div> <div class=sectline>a(n) = 1 for n >= 3. (End)</div> <div class=sectline>E.g.f.: exp(x) + 2 + 2*x + x^2/2. - <a href="/wiki/User:Elmo_R._Oliveira">Elmo R. Oliveira</a>, Aug 09 2024</div> </div> </div> <div class=section> <div class=sectname>EXAMPLE</div> <div class=sectbody> <div class=sectline>a(0) = H_0(1,2) = 2+1 = 3;</div> <div class=sectline>a(1) = H_1(1,2) = 1+2 = 3;</div> <div class=sectline>a(2) = H_2(1,2) = 1*2 = 2;</div> <div class=sectline>a(3) = H_3(1,2) = 1^2 = 1;</div> <div class=sectline>a(4) = H_4(1,2) = 1^^2 = 1.</div> </div> </div> <div class=section> <div class=sectname>CROSSREFS</div> <div class=sectbody> <div class=sectline>Cf. <a href="/A054871" title="a(n) = H_n(3,2) where H_n is the n-th hyperoperator.">A054871</a>.</div> <div class=sectline>Sequence in context: <a href="/A097278" title="Triangle read by rows: T(n, k) = number of permutations <p(1), p(2), ..., p(n)> of <1, 2, ..., n> that end with k, such that...">A097278</a> <a href="/A254411" title="Limit of f(f(f(...f(0))...) modulo n as the number of iterations of f(x)=2^x+1 grows.">A254411</a> <a href="/A056223" title="Hankel transform of partition numbers (A000041).">A056223</a> * <a href="/A100013" title="Number of prime factors in n!+7 (counted with multiplicity).">A100013</a> <a href="/A065744" title="Number of 9's in the decimal expansion of 2^n.">A065744</a> <a href="/A016455" title="Continued fraction for log(27).">A016455</a></div> <div class=sectline>Adjacent sequences: <a href="/A261140" title="a(n) = 3486107472997423 + (n-1)*371891575525470.">A261140</a> <a href="/A261141" title="Positive integers n that can be expressed as a product of Jacobsthal numbers (A001045), not necessarily distinct.">A261141</a> <a href="/A261142" title="Numbers n such that n, p=prime(n) and q=prime(p) have the same sum of digits.">A261142</a> * <a href="/A261144" title="Irregular triangle of numbers that are squarefree and smooth (row n contains squarefree p-smooth numbers, where p is the n-t...">A261144</a> <a href="/A261145" title="Numbers n such that n!3 + 3^10 is prime, where n!3 = n!!! is a triple factorial number (A007661).">A261145</a> <a href="/A261146" title="H_n(n,3) where H_n is the n-th hyperoperator.">A261146</a></div> </div> </div> <div class=section> <div class=sectname>KEYWORD</div> <div class=sectbody> <div class=sectline><span title="a sequence of nonnegative numbers">nonn</span>,<span title="a decimal expansion of a number"><a href="/A261143/constant">cons</a></span>,<span title="it is very easy to produce terms of sequence">easy</span></div> </div> </div> <div class=section> <div class=sectname>AUTHOR</div> <div class=sectbody> <div class=sectline><a href="/wiki/User:Natan_Arie_Consigli">Natan Arie Consigli</a>, Aug 24 2015</div> </div> </div> <div class=section> <div class=sectname>STATUS</div> <div class=sectbody> <div class=sectline>approved</div> </div> </div> </div> <div class=space10></div> </div> </div></div> <p> <div class=footerpad></div> <div class=footer> <center> <div class=bottom> <div class=linksbar> <a href="/">Lookup</a> <a href="/wiki/Welcome"><font color="red">Welcome</font></a> <a href="/wiki/Main_Page"><font color="red">Wiki</font></a> <a href="/wiki/Special:RequestAccount">Register</a> <a href="/play.html">Music</a> <a href="/plot2.html">Plot 2</a> <a href="/demo1.html">Demos</a> <a href="/wiki/Index_to_OEIS">Index</a> <a href="/webcam">WebCam</a> <a href="/Submit.html">Contribute</a> <a href="/eishelp2.html">Format</a> <a href="/wiki/Style_Sheet">Style Sheet</a> <a href="/transforms.html">Transforms</a> <a href="/ol.html">Superseeker</a> <a href="/recent">Recents</a> </div> <div class=linksbar> <a href="/community.html">The OEIS Community</a> </div> <div class=linksbar> Maintained by <a href="http://oeisf.org">The OEIS Foundation Inc.</a> </div> <div class=dbinfo>Last modified December 11 19:22 EST 2024. Contains 378623 sequences.</div> <div class=legal> <a href="/wiki/Legal_Documents">License Agreements, Terms of Use, Privacy Policy</a> </div> </div> </center> </div> </body> </html>