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 A255951 #4 Mar 11 2015 20:44:45 %S A255951 0,2,8,33,144,675,3396,18270,104656,635679,4078460,27544781,195219624, %T A255951 1447922814,11210516128,90405000105,757823763968,6591085453935, %U A255951 59379154929180,553270283842586,5324267165971800,52849751984814183,540469505506572620,5688102295215875017 %N A255951 Number of collections of nonempty multisets with a total of n+1 objects of exactly n colors. %H A255951 Alois P. Heinz, <a href="/A255951/b255951.txt">Table of n, a(n) for n = 0..250</a> %F A255951 a(n) = A255903(n+1,n). %Y A255951 A diagonal of A255903. %K A255951 nonn %O A255951 0,2 %A A255951 _Alois P. Heinz_, Mar 11 2015