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 A202250 #7 Jun 02 2025 07:24:49 %S A202250 1,7,57,509,4643,43293,408211,3882871,37183105,358012837,3462520849, %T A202250 33613331019,327348848723,3196657505737,31290407955317, %U A202250 306922478150245,3016082294628575,29687026287677819,292634127970865519 %N A202250 Number of zero-sum -6..6 arrays of n elements with adjacent element differences also in -6..6. %C A202250 Column 6 of A202252 %H A202250 R. H. Hardin, <a href="/A202250/b202250.txt">Table of n, a(n) for n = 1..210</a> %e A202250 Some solutions for n=6 %e A202250 .-2....4...-3....4....1....0...-2....3....6....3....0....2....3...-2....1....1 %e A202250 ..2....2...-2...-1...-3....0...-1...-3....1....0....2...-3....0...-3....4...-1 %e A202250 ..5....3....1...-4...-2....6....2...-4...-4....1...-1....0....5....1...-2...-4 %e A202250 ..1...-1....5...-5....3....1....1...-1...-6...-1....4...-3....0....1...-3...-1 %e A202250 .-3...-5....1....0...-2...-1....1....3...-1....1...-2...-1...-2....3...-3....4 %e A202250 .-3...-3...-2....6....3...-6...-1....2....4...-4...-3....5...-6....0....3....1 %K A202250 nonn %O A202250 1,2 %A A202250 _R. H. Hardin_ Dec 14 2011