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 A202667 #7 Jul 22 2025 16:45:51 %S A202667 23,613,6055,34171,136999,438177,1186107,2839237,6169921,12410957, %T A202667 23428771,41960815,71850731,118414399,188766767,292290383,441086445, %U A202667 650648037,940297237,1334163773,1861743181,2558935713,3468879881 %N A202667 Number of -n..n arrays of 7 elements with first through fourth differences also in -n..n. %C A202667 Row 7 of A202664 %H A202667 R. H. Hardin, <a href="/A202667/b202667.txt">Table of n, a(n) for n = 1..69</a> %e A202667 Some solutions for n=4 %e A202667 .-3...-2....4....0....0...-1...-4....1....1...-2....4....3....0...-3....1....0 %e A202667 ..1....1....2...-1...-1....0...-2...-2....0...-3....2....2....0...-1...-2....4 %e A202667 ..1....1....3....0...-2....1....0...-1....0...-2....2....3....0...-2...-2....4 %e A202667 ..0....1....3....1...-2....1....1....1....0...-1....1....3...-1...-3....0....3 %e A202667 .-2....2....1....0....0....0....2....1....0....1...-1....3...-2...-4....3....2 %e A202667 .-3....3....0...-1....2....0....1....0....0....4...-1....3...-2...-3....3...-1 %e A202667 .-4....1....2....2....2....2...-1....1....2....4....0....1...-4...-2....0...-4 %K A202667 nonn %O A202667 1,1 %A A202667 _R. H. Hardin_ Dec 22 2011