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 A254233 #36 Apr 24 2015 18:37:26
%S A254233 1,1,4,10,25,49,103,184,331,554,911,1424,2204,3278,4817,6896,9746,
%T A254233 13487,18480,24882,33192,43683,56994,73512,94131,119340,150300,187732,
%U A254233 233065,287248,352153,428944,519949,626737,752095,897994,1067924,1264241,1491155,1751672
%N A254233 Number of ways to partition the multiset consisting of n copies each of 1, 2, and 3 into n sets of size 3.
%H A254233 Alois P. Heinz, <a href="/A254233/b254233.txt">Table of n, a(n) for n = 0..1000</a>
%F A254233 G.f.: (x^12-x^11+x^10+3*x^9+5*x^8+x^7+4*x^6+x^5+5*x^4+3*x^3+x^2-x+1) / ((x^2+1)*(x^2-x+1)*(x^2+x+1)^3*(x+1)^4*(x-1)^8). - _Alois P. Heinz_, Apr 21 2015
%e A254233 For n = 2, the set {1,1,2,2,3,3} can be partitioned into two sets in four ways: {{112},{233}}, {{113},{223}}, {{122},{133}}, and {{123},{123}}.
%Y A254233 Cf. A002135, A254243.
%Y A254233 Column k=3 of A257462.
%K A254233 nonn,easy
%O A254233 0,3
%A A254233 _Tatsuru Murai_, Jan 27 2015
%E A254233 Fixed definition and examples by _Kellen Myers_, Apr 21 2015
%E A254233 a(14)-a(39) from _Alois P. Heinz_, Apr 21 2015