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 A104385 #9 Feb 26 2014 08:31:51
%S A104385 0,0,1,4,12,27,52,91,147,225,331,469,645,867,1141,1474,1875,2352,2914,
%T A104385 3571,4332,5208,6211,7351,8640,10092,11719,13534,15552,17787,20254,
%U A104385 22969,25947,29205,32761,36631,40833,45387,50311,55624
%N A104385 Number of distinct partitions of triangular numbers n*(n+1)/2 into 3 parts for n>=1.
%C A104385 Equals the third column in triangle A104382.
%F A104385 a(n) = round((3n^4 + 6n^3 - 33n^2 - 36n + 110)/144) (conjectured). - _Ralf Stephan_, Nov 13 2010.
%o A104385 (PARI) {a(n)=if(n<1,0,polcoeff(polcoeff( prod(i=1,n*(n+1)/2,1+y*x^i,1+x*O(x^(n*(n+1)/2))),n*(n+1)/2,x),3,y))}
%Y A104385 Cf. A000009, A104382.
%K A104385 nonn
%O A104385 1,4
%A A104385 _Paul D. Hanna_, Mar 04 2005