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 A259249 #6 Jun 02 2025 11:49:54 %S A259249 1353,15613,159168,1803859,18970267,211569948,2259371001,24946035357, %T A259249 268635598788,2948447364239,31900157480147,348917447759080, %U A259249 3785118935837593,41318554169121573,448913396152129472 %N A259249 Number of (n+1)X(7+1) 0..1 arrays with each 2X2 subblock having clockwise pattern 0000 0011 or 0111. %C A259249 Column 7 of A259250 %H A259249 R. H. Hardin, <a href="/A259249/b259249.txt">Table of n, a(n) for n = 1..210</a> %H A259249 R. H. Hardin, <a href="/A259249/a259249.txt">Empirical recurrence of order 54</a> %F A259249 Empirical recurrence of order 54 (see link above) %e A259249 Some solutions for n=3 %e A259249 ..0..1..1..1..1..1..0..0....1..1..0..0..1..0..0..1....0..1..0..0..1..0..1..0 %e A259249 ..0..1..0..0..0..1..0..0....0..1..1..1..1..1..1..1....0..1..1..1..1..1..1..1 %e A259249 ..1..1..1..1..1..1..1..1....0..1..0..0..0..1..0..0....0..1..0..1..0..0..0..1 %e A259249 ..1..0..0..0..1..0..0..0....1..1..1..1..1..1..1..1....0..1..1..1..0..0..0..1 %Y A259249 Cf. A259250 %K A259249 nonn %O A259249 1,1 %A A259249 _R. H. Hardin_, Jun 22 2015