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 A214113 #8 Jul 22 2025 23:08:38 %S A214113 4,11,111,670,4994,34041,241021,1678940,11777184,82366471,576786731, %T A214113 4036842810,28259892574,197813269301,1384710821241,9692921940280, %U A214113 67850615007164,474953820774531,3324678198248551,23272743029259350 %N A214113 Number of 0..3 colorings of a 2X(n+1) array circular in the n+1 direction with new values 0..3 introduced in row major order. %C A214113 Row 2 of A214112 %H A214113 R. H. Hardin, <a href="/A214113/b214113.txt">Table of n, a(n) for n = 1..210</a> %F A214113 Empirical: a(n) = 4*a(n-1) +22*a(n-2) -4*a(n-3) -21*a(n-4). %F A214113 Empirical: G.f. -x*(7*x+4)*(3*x-1) / ( (x-1)*(3*x+1)*(7*x-1)*(1+x) ), a(n) = 11/24 +3*(-1)^(n+1)/8 +7^(n+1)/24 +(-3)^(n+1)/8. - _R. J. Mathar_, Jul 04 2012 %e A214113 Some solutions for n=4 %e A214113 ..0..1..0..2..3....0..1..2..0..1....0..1..2..3..1....0..1..2..0..3 %e A214113 ..1..2..1..3..0....1..2..3..1..0....3..2..0..1..2....3..0..1..2..0 %K A214113 nonn %O A214113 1,1 %A A214113 _R. H. Hardin_ Jul 04 2012