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 A200270 #7 Feb 06 2025 15:36:23 %S A200270 1,7,13,25,37,53,53,83,119,261,477,955,615,1617,937,2447,5409,13829, %T A200270 9379,17547 %N A200270 Number of 0..6 arrays x(0..n+1) of n+2 elements with zero (n-1)th differences. %e A200270 Some solutions for n=6: %e A200270 ..5....5....6....4....1....0....3....5....6....4....5....6....0....1....2....5 %e A200270 ..6....0....6....4....5....5....1....1....6....6....4....1....1....2....4....0 %e A200270 ..5....0....6....4....6....5....3....0....6....4....5....1....0....1....2....0 %e A200270 ..3....1....6....4....5....3....5....0....5....2....6....2....0....0....0....2 %e A200270 ..1....1....6....4....3....1....5....0....3....2....6....2....2....0....0....4 %e A200270 ..0....0....6....4....1....0....3....0....1....4....5....1....5....1....2....5 %e A200270 ..1....0....6....4....0....0....1....1....1....6....4....1....6....2....4....5 %e A200270 ..5....5....6....4....1....0....3....5....6....4....5....6....0....1....2....5 %Y A200270 Column 6 of A200272. %K A200270 nonn %O A200270 1,2 %A A200270 _R. H. Hardin_, Nov 15 2011