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 A300771 #4 Mar 12 2018 11:25:39 %S A300771 0,2,3,11,32,102,330,1059,3418,11023,35561,114744,370251,1194696, %T A300771 3854994,12439181,40138345,129517277,417922738,1348541219,4351434893, %U A300771 14041088118,45307389076,146196612400,471743129235,1522207498886,4911816468097 %N A300771 Number of nX3 0..1 arrays with every element equal to 2, 3, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. %C A300771 Column 3 of A300776. %H A300771 R. H. Hardin, <a href="/A300771/b300771.txt">Table of n, a(n) for n = 1..210</a> %F A300771 Empirical: a(n) = 3*a(n-1) +3*a(n-3) -3*a(n-4) +5*a(n-5) -2*a(n-6) -11*a(n-7) -13*a(n-8) +11*a(n-9) -2*a(n-10) -5*a(n-11) +a(n-12) +5*a(n-13) -4*a(n-14) +a(n-15) %e A300771 Some solutions for n=5 %e A300771 ..0..0..1. .0..0..0. .0..0..1. .0..0..1. .0..0..1. .0..0..1. .0..0..1 %e A300771 ..0..1..1. .0..0..1. .0..1..1. .0..1..1. .0..1..1. .0..1..1. .0..1..1 %e A300771 ..1..1..1. .0..1..1. .0..0..0. .0..0..0. .0..1..1. .1..1..1. .0..1..1 %e A300771 ..0..0..1. .0..1..0. .1..1..0. .0..0..1. .0..1..0. .1..1..0. .0..0..1 %e A300771 ..0..1..1. .0..0..0. .1..0..0. .0..1..1. .0..0..0. .1..0..0. .0..1..1 %Y A300771 Cf. A300776. %K A300771 nonn %O A300771 1,2 %A A300771 _R. H. Hardin_, Mar 12 2018