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 A250275 #5 Jul 23 2025 12:16:20 %S A250275 7,67,207,1991,14003,130335,1154141,10172515,86975297,715749943, %T A250275 5655832367,43083514447,318775210489,2309920909887 %N A250275 Number of length n+1 0..6 arrays with the sum of the squares of adjacent differences multiplied by some arrangement of +-1 equal to zero. %C A250275 Column 6 of A250277 %e A250275 Some solutions for n=6 %e A250275 ..2....1....2....2....2....4....4....4....3....6....2....4....2....4....6....0 %e A250275 ..4....2....3....4....3....1....0....3....1....1....4....2....2....4....3....2 %e A250275 ..0....0....0....6....6....4....6....6....6....6....1....3....1....4....2....5 %e A250275 ..4....2....0....1....5....6....2....4....4....3....0....5....5....1....6....4 %e A250275 ..3....3....2....4....5....3....5....2....4....5....1....0....4....5....1....1 %e A250275 ..0....0....4....5....2....5....4....3....5....6....0....6....1....0....5....2 %e A250275 ..2....3....0....0....6....2....6....4....1....4....2....4....6....0....4....0 %K A250275 nonn %O A250275 1,1 %A A250275 _R. H. Hardin_, Nov 16 2014