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 A200464 #7 Jun 02 2025 07:18:20 %S A200464 4,10,26,69,181,455,1120,2794,6955,17254,42770,105825,262026,648672, %T A200464 1605786,3974375,9835789,24343416,60250311,149117782,369056036, %U A200464 913396093,2260628044,5594995167,13847440350,34272006253,84822308047,209933077581 %N A200464 Number of 0..3 arrays x(0..n-1) of n elements with each no smaller than the sum of its four previous neighbors modulo 4. %C A200464 Column 3 of A200469 %H A200464 R. H. Hardin, <a href="/A200464/b200464.txt">Table of n, a(n) for n = 1..210</a> %e A200464 Some solutions for n=6 %e A200464 ..2....0....1....2....0....0....1....0....0....0....0....2....3....2....2....0 %e A200464 ..3....0....3....2....0....0....3....3....1....0....2....2....3....3....2....1 %e A200464 ..1....2....2....1....3....1....0....3....3....1....2....0....2....3....2....3 %e A200464 ..3....2....2....3....3....3....0....2....1....3....0....3....1....2....2....0 %e A200464 ..1....1....2....1....2....1....2....0....3....3....0....3....1....2....3....1 %e A200464 ..2....3....2....3....3....3....2....1....3....3....2....1....3....2....3....3 %K A200464 nonn %O A200464 1,1 %A A200464 _R. H. Hardin_ Nov 18 2011