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 A183915 #7 Jul 22 2025 09:18:08 %S A183915 1,8,32,126,414,1242,3370,8512,20094,44916,95514,194668,381676,723354, %T A183915 1328980,2374753,4136477,7040196,11728606,19159798,30734578,48479188, %U A183915 75277670,115195490,173885716,259140928,381577586,555546058,800247348 %N A183915 Number of nondecreasing arrangements of n numbers in -7..7 with sum zero. %C A183915 Column 7 of A183917 %H A183915 R. H. Hardin, <a href="/A183915/b183915.txt">Table of n, a(n) for n = 1..71</a> %e A183915 Some solutions for n=4 %e A183915 .-6...-6...-4...-2...-3...-5...-7...-6...-3...-5...-5...-2...-3...-1...-7...-2 %e A183915 .-2...-1...-4...-2...-1...-3....0...-3...-1...-2...-1....0...-2...-1...-7...-2 %e A183915 ..2....0....4....0....1....4....0....4....2....3....3....1....1....0....7....1 %e A183915 ..6....7....4....4....3....4....7....5....2....4....3....1....4....2....7....3 %K A183915 nonn %O A183915 1,2 %A A183915 _R. H. Hardin_ Jan 07 2011