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 A297715 #4 Jan 04 2018 21:55:16 %S A297715 4,34,145,747,4090,21116,110551,582755,3055652,16036278,84225551, %T A297715 442157803,2321279598,12187515422,63986012963,335934438957, %U A297715 1763713210610,9259764998068,48615161059469,255237152397199,1340034403055100 %N A297715 Number of nX3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 2 or 4 neighboring 1s. %C A297715 Column 3 of A297720. %H A297715 R. H. Hardin, <a href="/A297715/b297715.txt">Table of n, a(n) for n = 1..210</a> %F A297715 Empirical: a(n) = a(n-1) +8*a(n-2) +64*a(n-3) +85*a(n-4) +19*a(n-5) -569*a(n-6) -1161*a(n-7) -1173*a(n-8) +125*a(n-9) +1720*a(n-10) +1802*a(n-11) +1328*a(n-12) +240*a(n-13) %e A297715 Some solutions for n=7 %e A297715 ..0..1..0. .1..1..1. .1..1..1. .1..0..0. .1..0..0. .1..1..0. .0..1..1 %e A297715 ..0..0..1. .1..0..1. .1..0..1. .0..1..1. .0..1..0. .1..0..0. .1..0..0 %e A297715 ..0..0..0. .0..1..1. .0..1..1. .0..1..0. .0..0..0. .0..1..0. .0..0..0 %e A297715 ..0..0..0. .0..0..1. .0..0..1. .0..0..0. .0..1..1. .0..1..0. .1..1..0 %e A297715 ..1..0..1. .1..0..1. .0..1..0. .0..1..1. .0..0..0. .1..0..1. .0..0..1 %e A297715 ..1..1..1. .0..1..1. .1..0..0. .0..1..0. .1..1..0. .1..1..1. .0..1..0 %e A297715 ..0..1..0. .0..1..1. .0..1..0. .0..1..1. .0..0..0. .0..0..0. .0..0..1 %Y A297715 Cf. A297720. %K A297715 nonn %O A297715 1,1 %A A297715 _R. H. Hardin_, Jan 04 2018