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 A297596 #8 Mar 01 2019 14:53:14 %S A297596 1,9,25,49,145,443,1141,3009,8455,23151,62211,169651,464469,1262947, %T A297596 3434407,9364725,25517397,69467533,189209921,515479315,1403998341, %U A297596 3823905513,10415880295,28371283095,77275911315,210482481315 %N A297596 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 5 neighboring 1s. %H A297596 R. H. Hardin, <a href="/A297596/b297596.txt">Table of n, a(n) for n = 1..210</a> %F A297596 Empirical: a(n) = a(n-1) + a(n-2) + 8*a(n-3) + 7*a(n-4) - 8*a(n-6) - 6*a(n-7). %F A297596 Empirical g.f.: x*(1 + 8*x + 15*x^2 + 7*x^3 - 8*x^4 - 14*x^5 - 6*x^6) / (1 - x - x^2 - 8*x^3 - 7*x^4 + 8*x^6 + 6*x^7). - _Colin Barker_, Mar 01 2019 %e A297596 Some solutions for n=7: %e A297596 ..1..0..0..1..1..0..0. .0..0..0..1..1..0..0. .1..0..1..0..0..0..0 %e A297596 ..0..1..0..0..0..0..0. .0..1..0..0..0..0..0. .1..1..1..0..0..1..0 %e A297596 ..0..0..0..0..0..0..0. .1..0..0..0..0..1..1. .1..0..0..0..0..0..1 %Y A297596 Row 3 of A297595. %K A297596 nonn %O A297596 1,2 %A A297596 _R. H. Hardin_, Jan 01 2018