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 A203972 #7 Jul 22 2025 17:41:54 %S A203972 13,396,16723,601521,22100882,817293052,30104480870,1109867821460, %T A203972 40918040450898,1508399380147856,55608018263653107, %U A203972 2050003686321969840,75573742529524147667,2786045396078461420336,102708210001323641444431 %N A203972 Number of nX5 0..2 arrays with every 1 immediately preceded by 0 to the left or above, and every 2 immediately preceded by 0 1 to the left or above. %C A203972 Column 5 of A203975 %H A203972 R. H. Hardin, <a href="/A203972/b203972.txt">Table of n, a(n) for n = 1..210</a> %e A203972 Some solutions for n=3 %e A203972 ..0..0..0..0..1....0..1..0..1..0....0..0..0..0..1....0..0..0..0..0 %e A203972 ..1..1..1..0..1....0..1..2..0..0....0..1..1..1..0....0..1..2..1..0 %e A203972 ..2..0..0..1..2....1..0..0..0..0....1..2..0..0..1....0..0..1..0..1 %K A203972 nonn %O A203972 1,1 %A A203972 _R. H. Hardin_ Jan 08 2012