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 A230187 #7 Jun 02 2025 08:42:43 %S A230187 0,129,1971,73857,2432241,82359177,2770525761,93340154655, %T A230187 3143682463065,105885454704267,3566387657985771,120121801796361177, %U A230187 4045897974546191799,136272446957010253599,4589878342395006746985,154594591461184687863333 %N A230187 Number of 4Xn 0..2 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value 2-x(i,j). %C A230187 Row 4 of A230184 %H A230187 R. H. Hardin, <a href="/A230187/b230187.txt">Table of n, a(n) for n = 1..210</a> %H A230187 R. H. Hardin, <a href="/A230187/a230187.txt">Empirical recurrence of order 93</a> %F A230187 Empirical recurrence of order 93 (see link above) %e A230187 Some solutions for n=3 %e A230187 ..2..0..1....2..0..1....2..0..0....1..1..1....2..0..2....2..0..2....1..1..1 %e A230187 ..1..1..2....1..1..2....2..2..0....0..2..0....0..2..2....2..2..0....1..0..2 %e A230187 ..2..0..2....1..0..2....2..0..0....1..1..0....0..0..2....2..0..0....2..1..1 %e A230187 ..2..0..2....2..0..2....2..2..0....1..2..0....2..0..2....2..2..0....1..2..0 %K A230187 nonn %O A230187 1,2 %A A230187 _R. H. Hardin_, Oct 11 2013