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 A104384 #18 Aug 01 2020 11:38:57
%S A104384 1,4,12,27,57,110,201,352,598,984,1586,2503,3882,5928,8932,13287,
%T A104384 19551,28472,41078,58754,83372,117417,164230,228212,315190,432817,
%U A104384 591130,803192,1086035,1461680,1958596,2613417,3473190,4598073,6064920,7971480
%N A104384 Number of partitions of triangular numbers n*(n+1)/2 into (n-2) distinct parts for n>=3.
%C A104384 In triangle A104382, equals the second diagonal down from the main diagonal.
%C A104384 Also equals a diagonal with slope -3 in the Partition Numbers triangle A008284, found at n = 3+3k, or T(3+3k,k) for k >=1. - _Richard R. Forberg_, Dec 02 2014
%H A104384 Vaclav Kotesovec, <a href="/A104384/b104384.txt">Table of n, a(n) for n = 3..132</a>
%F A104384 From _Álvar Ibeas_, Jul 23 2020: (Start)
%F A104384 Writing p(m) for A000041(m),
%F A104384 a(n) = p(2n-1) - A000070(n) + 1 and
%F A104384 a(n+1) - a(n) = p(2*n+1) - p(2*n-1) - p(n+1) = A027336(2*n+1) - p(n+1).
%F A104384 (End)
%o A104384 (PARI) {a(n)=if(n<3,0,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),n-2,y))}
%Y A104384 Cf. A000009, A104382, A008284.
%K A104384 nonn
%O A104384 3,2
%A A104384 _Paul D. Hanna_, Mar 04 2005