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 A302474 #9 Aug 02 2025 12:16:28 %S A302474 0,34,250,1401,10264,78679,584333,4330427,32116855,238854305, %T A302474 1774890111,13186901755,97987405188,728115173717,5410378555145, %U A302474 40202636764567,298731900955463,2219776401635593,16494405056538952,122564331015474402,910734015368035169,6767355923137558997 %N A302474 Number of 4 X n 0..1 arrays with every element equal to 1, 2, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %H A302474 R. H. Hardin, <a href="/A302474/b302474.txt">Table of n, a(n) for n = 1..210</a> %H A302474 R. H. Hardin, <a href="/A302474/a302474.txt">Empirical recurrence of order 63</a> %F A302474 Empirical recurrence of order 63 (see link above). %e A302474 Some solutions for n=5: %e A302474 ..0..0..1..1..0. .0..1..0..0..1. .0..0..0..1..1. .0..0..1..1..0 %e A302474 ..1..1..1..0..1. .1..0..1..1..0. .1..1..0..0..1. .1..1..1..0..0 %e A302474 ..0..1..0..0..0. .0..0..1..1..0. .0..1..1..0..1. .1..0..1..0..1 %e A302474 ..0..0..1..1..0. .0..1..1..0..0. .0..0..0..1..1. .0..0..0..1..0 %Y A302474 Row 4 of A302472. %K A302474 nonn %O A302474 1,2 %A A302474 _R. H. Hardin_, Apr 08 2018