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 A298138 #4 Jan 13 2018 11:14:30 %S A298138 0,34,6,185,627,3417,14422,73961,354200,1772595,8807624,44087860, %T A298138 218942205,1093100404,5447861031,27173970577,135547796845, %U A298138 676389434363,3374295032672,16836823878509,84007635799139,419167042007303 %N A298138 Number of nX7 0..1 arrays with every element equal to 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero. %C A298138 Column 7 of A298139. %H A298138 R. H. Hardin, <a href="/A298138/b298138.txt">Table of n, a(n) for n = 1..210</a> %e A298138 Some solutions for n=7 %e A298138 ..0..0..1..0..1..1..1. .0..0..0..1..1..0..0. .0..0..1..0..0..1..1 %e A298138 ..0..1..0..1..0..0..1. .1..0..1..1..0..1..0. .0..1..1..1..0..0..1 %e A298138 ..0..1..0..1..0..1..0. .1..1..1..1..0..0..1. .1..0..0..0..1..0..1 %e A298138 ..0..1..0..1..0..1..0. .1..0..0..1..1..1..1. .0..1..1..0..1..0..1 %e A298138 ..0..1..0..1..0..1..0. .1..0..1..0..1..1..0. .0..0..1..0..1..0..1 %e A298138 ..0..1..1..0..1..0..1. .0..1..1..0..1..0..0. .1..0..1..0..1..0..1 %e A298138 ..0..0..0..0..0..1..1. .0..0..0..1..1..1..0. .1..1..0..1..0..1..1 %Y A298138 Cf. A298139. %K A298138 nonn %O A298138 1,2 %A A298138 _R. H. Hardin_, Jan 13 2018