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 A297310 #7 Feb 26 2019 12:06:16 %S A297310 7,66,497,3808,29212,223995,1717882,13174266,101033369,774822892, %T A297310 5942100272,45569854023,349474289622,2680111429330,20553721242845, %U A297310 157626080234992,1208831279237072,9270503076704855,71095304015354510 %N A297310 Number of n X 4 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 or 2 neighboring 1s. %H A297310 R. H. Hardin, <a href="/A297310/b297310.txt">Table of n, a(n) for n = 1..210</a> %F A297310 Empirical: a(n) = 4*a(n-1) + 26*a(n-2) + 22*a(n-3) - 43*a(n-4) - a(n-5) + 7*a(n-6) - a(n-7) - a(n-8) for n>9. %F A297310 Empirical g.f.: x*(7 + 38*x + 51*x^2 - 50*x^3 - 93*x^4 + 50*x^5 + 2*x^6 - 10*x^7 + x^8) / ((1 - 7*x - 5*x^2 - x^3)*(1 + 3*x - 6*x^3 + 4*x^4 - x^5)). - _Colin Barker_, Feb 26 2019 %e A297310 Some solutions for n=5: %e A297310 ..0..1..1..0. .1..1..0..1. .1..1..1..0. .0..1..1..0. .0..0..1..1 %e A297310 ..1..0..0..1. .0..0..1..1. .0..1..0..1. .1..1..0..0. .0..1..0..1 %e A297310 ..0..1..1..0. .0..0..1..1. .1..0..1..0. .0..1..0..0. .1..0..1..1 %e A297310 ..1..0..0..0. .0..0..0..0. .0..1..0..0. .1..0..1..0. .0..0..0..1 %e A297310 ..1..1..1..0. .0..1..1..0. .0..1..1..0. .1..1..0..0. .1..1..1..0 %Y A297310 Column 4 of A297314. %K A297310 nonn %O A297310 1,1 %A A297310 _R. H. Hardin_, Dec 28 2017