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 A223602 #6 Jul 23 2025 04:17:18 %S A223602 65536,7424,176224,2372080,43725920,755683024,13959069888, %T A223602 258174966416,4850832343904,91505981537072,1733729781877920, %U A223602 32909491571349680,625534833011886880,11898376530083012208,226422016143905134464 %N A223602 Petersen graph (8,2) coloring a rectangular array: number of 4Xn 0..15 arrays where 0..15 label nodes of a graph with edges 0,1 0,8 8,14 8,10 1,2 1,9 9,15 9,11 2,3 2,10 10,12 3,4 3,11 11,13 4,5 4,12 12,14 5,6 5,13 13,15 6,7 6,14 7,0 7,15 and every array movement to a horizontal, diagonal or antidiagonal neighbor moves along an edge of this graph. %C A223602 Row 4 of A223599 %H A223602 R. H. Hardin, <a href="/A223602/b223602.txt">Table of n, a(n) for n = 1..210</a> %F A223602 Empirical: a(n) = 22*a(n-1) +146*a(n-2) -4241*a(n-3) -7021*a(n-4) +296069*a(n-5) +84524*a(n-6) -10098300*a(n-7) +2841988*a(n-8) +193753372*a(n-9) -109915280*a(n-10) -2243896688*a(n-11) +1623516032*a(n-12) +16219469440*a(n-13) -13091056384*a(n-14) -74162963712*a(n-15) +62602426368*a(n-16) +215343361024*a(n-17) -182965936128*a(n-18) -395412119552*a(n-19) +329698951168*a(n-20) +450438201344*a(n-21) -361766191104*a(n-22) -303199682560*a(n-23) +230835617792*a(n-24) +107843944448*a(n-25) -76487327744*a(n-26) -15032385536*a(n-27) +9663676416*a(n-28) for n>29 %e A223602 Some solutions for n=3 %e A223602 ..0..8..0....1..2.10....8.14..8....8.14..8....8.10..8....8..0..1....5..4..3 %e A223602 ..0..1..0....1..2..3....8..0..8....8.10..8...12.14..8....7..0..8....3..4..3 %e A223602 ..0..1..0...10..2..3....7..0..7....8..0..8....6.14..6....7..0..8....5..4..5 %e A223602 ..9..1..2....1..2..1....7..0..8....8..0..8...12.14.12....1..0..7....5.13..5 %K A223602 nonn %O A223602 1,1 %A A223602 _R. H. Hardin_ Mar 23 2013