CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "oeis.org",cType: 'managed',cRay: '92c2de946b4740b0',cH: 'VOLOz1EvMiIGFOyYrJ.IzeHNj7Pz.ijtNPj8yNIzYJk-1743959120-1.2.1.1-Tu.MxZAke2.jsyyukOlbLcIqD23oOyxvDu20uym7i0RfEvGZDsIUeZqIW4iNJRn6',cUPMDTk: "\/A5564?__cf_chl_tk=BCLYr.TwNfgf0k3bji_uyW7gbF0a8h1WxvUAqgTU9Tc-1743959120-1.0.1.1-NRyKS31MX5EQNzQfXkpV6RSIUGq70CCi.3W.5HumIn4",cFPWv: 'g',cITimeS: '1743959120',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/A5564?__cf_chl_f_tk=BCLYr.TwNfgf0k3bji_uyW7gbF0a8h1WxvUAqgTU9Tc-1743959120-1.0.1.1-NRyKS31MX5EQNzQfXkpV6RSIUGq70CCi.3W.5HumIn4",md: "AQxda0WwlBXTnOA_6d7S4u2siyLUWchzWwe0YUjz_eA-1743959120-1.2.1.1-w185xdCEav2_CkBYTvAflb4FRBrHiV3ZqPTBujNp2J_G6R46E_lflgdjqKRPR4PA7yQIY6pM5NY9H8mKmK3bnNLXdoi71ZUze.Kk_dkh1hUz_Q3EhbNCEJMmbqdDASA2IxM5M4EWVBzA_w9GudpH5bpgAy3uhhUSVVXmrcVLTue8z1CGUWqX.BQQ8WN..k6KWkqf0pQHP0m9b8FbhiPaSV3KryO.mGFw5jjN_uiakuYtMzrDCRjSdxn.d.dFu8GkmYhB_VoQWBK0Z.ebBAO5VdLbttSLPNmUB4h4vjKVAp8bRCF1.SeNwHHBivK12zQrtVhkJr48v3xkMzmWIIf8XppakYMDoCGmKCijx3wUhUrZPdyBmLNDfbP4SsIfW8cMvbkcCORMsJklADyhGaFaDRGdQIykrEGeasNyjJRAHubQlfXueQTt0bxDe1vCNdQSO8nGY5dOnAUsCIKgxit9iYrrWWMrGQlhyJI37S5OVW2lZd6T_gi10TN21JFUb8GvlHOoavF.Cnx3ZPwSZ6j_zZqarGu2k0YHW2ePpNjksb3HP40tBkldscGuHlvcnSb4ZdpWv1g860QZjsJXfGNPULjz3qWlZnDC_JVQI5uX3xZI6kzQHtVwUxXhiIYVYp7_auTb.4yDijMT1umuXlkr_XhhKQHF3NZRzG8z5vUvEVowqtKzOn.hd4zzYjT.MlvC4VWa7Hilon1RnflJyD2IBo7ZMqOyEBjNmc9inLD00Pup_byKWN9ycBbutCG6dFXCB_ITnmdHm9gqNTeq8gElhP8UGw2YRLbyKamW2nXXPx8iZlGIBiIMCIglG6GVIcelWMyjklrkqewvCo8wfHDZlGZRm9cNKtjQS8b3VAcFNSu0izJtwbBAEhXEL7hp6QJ85UGBHc.AgZpDHoDM2xFm4ClBN.tTODPdiiPXhbiAMSj2abo9_wZ4K4H2R0HVG2dUY_t1jXC4A3WRlCxGUrsciHjgzhp6RrEZpVcBQsc.7Pm1hKNakLHPggEZCJOep6rdgJ_STNqg6.MwuMzUzZijBZ0Tw7uCbtMVyTkKKRR1Z4ZtOxDQ6OVyKI__.aNw9yIp",mdrd: ".2mnxOn95p7M.9sHYvbybxEghUUkfxkemFMgAOW7wrA-1743959120-1.2.1.1-itpup3d2u4UnN6heRijZsoILkbCD4Yx8ISvvGGKvB7VIwHRGh49m7pDB_RCQ845D17jsakCfdUq.nNZY5W8v8iZ.9nasLceNSj11Vh4UZDbjgFaNfdOKrNVjeV4wHmQaTQrP6zlwRwlREBuCxRhtxhs5qu1gBjnPw.MGyLdRbTvf56dfHTUGCSQzJ3BruKqklqS_QqAYWEGOSFgO6UH.oex0u388VU0lnhqQtAXUF5ypIExwOEoY9grzuPR_fooM_EMd1y49PZZVRlby_KsC0_qS2k.Q3eU_1IhtBKFDIM4PFLG5DbQLUsLFerr4UufUAuaa9lrejKdg9h6.M34weYVOOljul9KJEDXio_nCoiSoF0xvKDWsxh.ZvchrNh9KrqZVGWHiLGoNE0F4IMA.GnMLySEsxI9vPerEUYadbeizeINcmhFMH9Ge3PcrLudPzdHDyfGCUWtHGph_zbxZ7Hkq3o3h4hGovgGeXMGPQ.1WH3NWDkP6ErM1bQKRwepKbhgLPdsdw21KanlZwko5ZEVtt0jvc.herdtDgkW7TCOLR8uathBc7mQBR7vf4VILm52OajsQcmEJ3I5f_neyFDP77d.WgFAPyrXJ2JVrK7DtQhBZLx9ECGzW7faCqDiy.P4rEEsefXIqzObX94osSMJJo1.9rBmLQbUGpcc4nneZgB9lwViloN1GCy3eIpN1nQ0j.cKRAsqz6e8a3D4sXzP0TDR.I_RmpqDShRXCtLd1UaqzU6L63c2Pb5kw49F7h5YsjleXk2NIXzPX7PzGRMimCv2SyEvSlfNZMLEHug8uLvhAD8Oi1oEGdjt2KQ1AC0ppl5U1ZFpsp5BkzzZ4Vkfj5x7GLx4_6P_93LnvTpy7lV1dLqWT7kUEm1L9pn197XiEdm4KaePhpvR_l83Rw7WSbzWu_HOyiBBeN42F5akUtfxn8lYWzdBB.CX_faj6cgCPLEoNl3LQE.gKg7CLJnXVX4V_iSU7HmEQGfnMNd0Cs58YGO_cB4m375W42v7tEvP89EMajAHWbT_PLxuaSLjLg5U6BnI_20Fyxc0SyiOQVZTrGKemlRokxZQU3NLOyQrZ7Nl9CoHvTr77O8zGM7qkhLVwo7M0hWxZ0GYT3E4mvxvRZ6F5mgA011GXw9hx9Rq69NpXgEoTxW2VU8fTtUzEOskdylsKnJOxOAK_a8icJYAqGyJZg3krY2HloM.O3G3XtjK79dEQLjnFaR7h6JsGq5n0jc4sGx_2eM3Z5Nr7JSE5R4r7n8dtVQynk6CzOYqrAb3BnGXLV5EQBE2ZMzIf7uMZroDjPgUPPlDeN74jCwn10wlMUl_LdTHoYHnSzmQD8WVZxN6bO5t4YYFsQRqW.SeEvb8gUr.GLWdlVg0Z7wnPr4XKjwycTz8z06PA.mDMbTppL1HTwjutryTORtNtm4SGALn.Kg_TSKl3GdkXy1DCjGhNb00R4gHZQF3p583czYvhgV2x1EIUDB2V7LhiJ1L4fkqq5H2xZE7Gh7c26s69yvntnVoxa4.7NYVO1pjNgUqExyTFF2_1GKKgFz69yzqIHbF5xKMCXnNfnZIr3QbMId6eF80xCSxliCz4fdiCeh9mkQzsK..LvuYmU.BaC23aMGlQrKb1H3Zi6Vb2h4.jikYVOJF.nwnMDHwgotJLaw1lFkDUqNV63OAdcKL3zXKtJUyaMAJ9aoyIa5_QfoR.WtoEwgMrzV76xFQ83BOaWOWHAldWvFxsa2Ox4031tSXf6tnw.Zq1H6bWPhvGJ2ec28D0huY115XORPCWTwnU8cP0eMnxbkCFZJVDvdfC2xECLNjePulWGCzZxwd7V5lU.sqO2TDhyYBVHqX8RXz4sOrl_yXEt1n82iyMHQKk1_.5qc0xsz7QLdZtgjmXq.1bL8n3tHslPnVbrvMSEELjkbVEfqsCu7v.VXSBsBKJRY2GcPcz8dBH_n9NTWkoN8JKRpiX0TpMwisVtA4F6lBL_qb2lr_E2fbCbdICD2jA7Y9_zQqmZFhfoeP6fiBMtOEQmliygD1zpSROqYph"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92c2de946b4740b0';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/A5564?__cf_chl_rt_tk=BCLYr.TwNfgf0k3bji_uyW7gbF0a8h1WxvUAqgTU9Tc-1743959120-1.0.1.1-NRyKS31MX5EQNzQfXkpV6RSIUGq70CCi.3W.5HumIn4" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>