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 A202961 #7 Jul 22 2025 16:53:48 %S A202961 128,1576,17296,207184,2537024,31155004,384996502,4786979780, %T A202961 59791891464,749603860520,9427927830076,118904758131236, %U A202961 1503198371854568,19043136745799960,241690849746856584,3072505406058890180 %N A202961 Number of arrays of n+2 integers in -7..7 with sum zero and adjacent elements differing in absolute value. %C A202961 Column 7 of A202962 %H A202961 R. H. Hardin, <a href="/A202961/b202961.txt">Table of n, a(n) for n = 1..210</a> %e A202961 Some solutions for n=3 %e A202961 ..4...-3....6...-6...-4...-7...-1....1...-3....0....1...-7....0....0....5....1 %e A202961 ..2....7....0....0...-6....1...-3....0...-4....7...-7...-1....2...-3....2....3 %e A202961 .-5....2...-7....5....0...-5....1....2....2...-6...-1....7....7....1...-4....1 %e A202961 ..6....0...-6...-3....4....4....0...-5...-1...-3....2....2...-3....0...-1...-5 %e A202961 .-7...-6....7....4....6....7....3....2....6....2....5...-1...-6....2...-2....0 %K A202961 nonn %O A202961 1,1 %A A202961 _R. H. Hardin_ Dec 26 2011