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 A214139 #6 Jul 22 2025 23:10:05 %S A214139 147,522515,2000093424,7658621867351,29325981412599886, %T A214139 112293482777565310571,429988214977169477452677, %U A214139 1646487940037763716348859705,6304643807380348053085274173830 %N A214139 Number of 0..4 colorings on an nX7 array circular in the 7 direction with new values 0..4 introduced in row major order. %C A214139 Column 6 of A214141 %H A214139 R. H. Hardin, <a href="/A214139/b214139.txt">Table of n, a(n) for n = 1..65</a> %F A214139 Empirical: a(n) = 4156*a(n-1) -1272609*a(n-2) +80884549*a(n-3) -1222656178*a(n-4) -19887912212*a(n-5) +527430399664*a(n-6) -2643328241280*a(n-7) +3940919419904*a(n-8) -1580167634944*a(n-9) %e A214139 Some solutions for n=4 %e A214139 ..0..1..2..0..2..0..1....0..1..2..3..4..0..4....0..1..0..1..2..1..2 %e A214139 ..1..2..3..1..3..4..0....4..2..4..1..2..1..3....1..0..2..3..1..2..0 %e A214139 ..4..3..2..3..4..3..1....1..0..1..3..4..0..4....2..4..3..4..2..3..1 %e A214139 ..3..4..0..1..2..0..2....3..2..0..1..3..1..0....0..3..2..1..3..4..2 %K A214139 nonn %O A214139 1,1 %A A214139 _R. H. Hardin_ Jul 05 2012