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 A214142 #16 Jul 15 2022 21:48:15 %S A214142 1,1,4,11,40,147,568,2227,8824,35123,140152,559923,2238328,8950579, %T A214142 35796856,143176499,572684152,2290692915,9162684280,36650562355, %U A214142 146601899896,586406900531,2345626204024,9382502019891,37530002487160 %N A214142 Number of 0..4 colorings of a 1 X (n+1) array circular in the n+1 direction with new values 0..4 introduced in row major order. %C A214142 Row 1 of A214141. %H A214142 R. H. Hardin, <a href="/A214142/b214142.txt">Table of n, a(n) for n = 1..210</a> %F A214142 Empirical: a(n) = 6*a(n-1) -7*a(n-2) -6*a(n-3) +8*a(n-4). %F A214142 Empirical: a(n) = 2^n/6 - 11*(-1)^n/30 + 4^n/30 + 1/6. - _R. J. Mathar_, Jul 07 2012 %F A214142 Empirical: partial sums of A110613. - _Sean A. Irvine_, Jul 14 2022 %e A214142 Some solutions for n=4: %e A214142 0 1 2 0 1 0 1 2 3 1 0 1 0 1 2 0 1 2 1 2 %K A214142 nonn %O A214142 1,3 %A A214142 _R. H. Hardin_, Jul 05 2012