This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A245873 #11 Nov 05 2018 03:05:18 %S A245873 26,239,676,1629,3102,5515,8840,13625,19810,28071,38316,51349,67046, %T A245873 86339,109072,136305,167850,204895,247220,296141,351406,414459,485016, %U A245873 564649,653042,751895,860860,981765,1114230,1260211,1419296,1593569 %N A245873 Number of length 4+2 0..n arrays with some pair in every consecutive three terms totalling exactly n. %H A245873 R. H. Hardin, <a href="/A245873/b245873.txt">Table of n, a(n) for n = 1..210</a> %F A245873 Empirical: a(n) = 3*a(n-1) - a(n-2) - 5*a(n-3) + 5*a(n-4) + a(n-5) - 3*a(n-6) + a(n-7). %F A245873 Conjectures from _Colin Barker_, Nov 04 2018: (Start) %F A245873 G.f.: x*(26 + 161*x - 15*x^2 - 30*x^3 - 44*x^4 - 3*x^5 + x^6) / ((1 - x)^5*(1 + x)^2). %F A245873 a(n) = 1 + 7*n + 20*n^2 + 16*n^3 + n^4 for n even. %F A245873 a(n) = -8 - 3*n + 20*n^2 + 16*n^3 + n^4 for n odd. %F A245873 (End) %e A245873 Some solutions for n=10: %e A245873 0 6 8 3 8 4 7 8 7 1 8 10 4 3 7 1 %e A245873 10 5 6 10 6 2 3 9 4 0 1 2 5 3 4 0 %e A245873 4 4 4 0 4 6 3 1 3 10 9 8 5 7 6 10 %e A245873 6 5 10 7 4 8 7 1 7 1 3 7 3 3 10 0 %e A245873 1 5 0 10 6 2 6 9 8 0 7 3 7 1 0 4 %e A245873 4 8 7 0 0 0 4 7 3 10 7 4 9 7 9 10 %Y A245873 Row 4 of A245869. %K A245873 nonn %O A245873 1,1 %A A245873 _R. H. Hardin_, Aug 04 2014