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 A302954 #4 Apr 16 2018 11:41:57 %S A302954 0,11,86,519,3626,26167,185810,1317541,9353154,66404553,471405566, %T A302954 3346494089,23756835310,168650322345,1197251824916,8499313431065, %U A302954 60336790015098,428332035511083,3040737367321452,21586253123647687 %N A302954 Number of 3Xn 0..1 arrays with every element equal to 1, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302954 Row 3 of A302953. %H A302954 R. H. Hardin, <a href="/A302954/b302954.txt">Table of n, a(n) for n = 1..210</a> %F A302954 Empirical: a(n) = 4*a(n-1) +15*a(n-2) +37*a(n-3) +80*a(n-4) +68*a(n-5) +26*a(n-6) +5*a(n-7) for n>9 %e A302954 Some solutions for n=5 %e A302954 ..0..0..0..1..1. .0..0..0..0..0. .0..1..0..0..0. .0..0..1..1..0 %e A302954 ..0..0..0..0..0. .0..0..1..1..1. .1..0..1..0..1. .1..1..0..0..1 %e A302954 ..1..1..0..1..1. .0..0..0..1..1. .0..1..1..1..0. .1..0..1..0..0 %Y A302954 Cf. A302953. %K A302954 nonn %O A302954 1,2 %A A302954 _R. H. Hardin_, Apr 16 2018