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 A245865 #11 Nov 05 2018 03:05:00 %S A245865 61,193,549,1629,4753,13961,40901,119953,351649,1031057,3022933, %T A245865 8863117,25986061,76189749,223384017,654949861,1920277409,5630150189, %U A245865 16507298221,48398515249,141901859897,416048676085,1219832512513,3576483842281 %N A245865 Number of length n+2 0..4 arrays with some pair in every consecutive three terms totalling exactly 4. %H A245865 R. H. Hardin, <a href="/A245865/b245865.txt">Table of n, a(n) for n = 1..210</a> %F A245865 Empirical: a(n) = 3*a(n-1) + a(n-2) - a(n-3) - 5*a(n-4) - 8*a(n-5) + 3*a(n-6). %F A245865 Empirical g.f.: x*(61 + 10*x - 91*x^2 - 150*x^3 - 185*x^4 + 75*x^5) / (1 - 3*x - x^2 + x^3 + 5*x^4 + 8*x^5 - 3*x^6). - _Colin Barker_, Nov 04 2018 %e A245865 Some solutions for n=8: %e A245865 1 1 0 4 1 3 2 0 0 0 1 4 2 2 1 3 %e A245865 2 4 1 1 0 0 2 1 2 4 0 0 3 2 3 0 %e A245865 3 0 3 3 4 4 0 3 2 4 3 1 1 0 1 4 %e A245865 2 4 1 0 3 0 4 1 1 0 1 4 2 4 2 2 %e A245865 2 4 1 4 1 3 2 2 2 4 1 0 3 0 2 2 %e A245865 0 0 3 0 3 1 2 2 3 2 3 3 1 1 2 0 %e A245865 2 4 3 4 2 0 0 4 1 2 4 1 0 3 2 4 %e A245865 2 3 1 0 1 3 2 0 3 1 0 4 4 1 4 3 %e A245865 0 1 3 4 2 1 2 2 4 3 1 0 0 4 0 0 %e A245865 2 4 1 3 2 3 4 2 1 3 4 1 1 0 4 1 %Y A245865 Column 4 of A245869. %K A245865 nonn %O A245865 1,1 %A A245865 _R. H. Hardin_, Aug 04 2014