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 A229591 #8 Apr 27 2021 21:23:14 %S A229591 0,5632,119232,2440692,47091780,890824020,16551428868,303527605644, %T A229591 5505540489756,98960332779288,1765177724896272,31280718324457188, %U A229591 551219288985891468,9666198588289311180,168785901193243289256 %N A229591 Number of defective 3-colorings of a 6 X n 0..2 array connected horizontally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order. %C A229591 Row 6 of A229586. %H A229591 R. H. Hardin, <a href="/A229591/b229591.txt">Table of n, a(n) for n = 1..210</a> %F A229591 Empirical: a(n) = 60*a(n-1) - 1466*a(n-2) + 19056*a(n-3) - 143515*a(n-4) + 608478*a(n-5) - 957350*a(n-6) - 3924114*a(n-7) + 27201539*a(n-8) - 68079378*a(n-9) + 46537423*a(n-10) + 212613240*a(n-11) - 785654632*a(n-12) + 1389943104*a(n-13) - 1544105168*a(n-14) + 1125401088*a(n-15) - 524553472*a(n-16) + 142135296*a(n-17) - 17040384*a(n-18) for n > 26. %e A229591 Some solutions for n=3: %e A229591 0 1 0 0 1 2 0 1 2 0 1 0 0 1 2 0 1 2 0 0 1 %e A229591 0 2 1 2 0 1 2 0 2 2 1 2 0 1 0 0 1 2 1 2 1 %e A229591 2 0 2 2 0 1 1 1 2 2 0 1 0 2 0 2 0 0 0 2 0 %e A229591 2 1 2 2 1 0 0 1 0 2 0 0 1 2 1 2 1 0 0 2 1 %e A229591 2 1 2 0 2 0 2 1 0 1 2 1 0 1 2 2 1 0 1 0 2 %e A229591 0 1 0 0 2 1 0 1 0 1 2 1 0 1 0 0 1 2 2 0 2 %Y A229591 Cf. A229586. %K A229591 nonn %O A229591 1,2 %A A229591 _R. H. Hardin_, Sep 26 2013