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 A250224 #6 Apr 18 2023 08:40:11 %S A250224 4,20,52,208,704,2720,10952,45888,195516,852260,3760588,16656832, %T A250224 73584076,323148964,1409241264,6099051768,26171960056,111250573364, %U A250224 468230400620,1951667338228,8063089066756,33057662096520,134680763671240 %N A250224 Number of length n+1 0..3 arrays with the sum of the cubes of adjacent differences multiplied by some arrangement of +-1 equal to zero. %C A250224 Column 3 of A250229. %H A250224 R. H. Hardin, <a href="/A250224/b250224.txt">Table of n, a(n) for n = 1..29</a> %e A250224 Some solutions for n=6 %e A250224 ..2....2....3....2....2....2....2....2....0....2....0....2....1....2....2....1 %e A250224 ..3....1....2....2....3....1....0....0....0....2....0....2....2....3....2....2 %e A250224 ..2....2....2....2....1....3....2....1....0....2....3....3....1....2....1....2 %e A250224 ..3....1....1....1....3....3....1....2....1....3....0....2....1....3....0....3 %e A250224 ..1....3....2....0....2....3....1....3....2....0....3....3....2....3....1....2 %e A250224 ..3....2....3....1....3....1....0....2....0....3....3....2....3....3....0....2 %e A250224 ..2....0....3....2....2....0....0....0....2....2....0....2....3....2....0....3 %Y A250224 Cf. A250229. %K A250224 nonn %O A250224 1,1 %A A250224 _R. H. Hardin_, Nov 14 2014