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A104384
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Number of partitions of triangular numbers n*(n+1)/2 into (n-2) distinct parts for n>=3.
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4
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1, 4, 12, 27, 57, 110, 201, 352, 598, 984, 1586, 2503, 3882, 5928, 8932, 13287, 19551, 28472, 41078, 58754, 83372, 117417, 164230, 228212, 315190, 432817, 591130, 803192, 1086035, 1461680, 1958596, 2613417, 3473190, 4598073, 6064920, 7971480
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OFFSET
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3,2
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COMMENTS
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In triangle A104382, equals the second diagonal down from the main diagonal.
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
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LINKS
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FORMULA
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a(n) = p(2n-1) - A000070(n) + 1 and
a(n+1) - a(n) = p(2*n+1) - p(2*n-1) - p(n+1) = A027336(2*n+1) - p(n+1).
(End)
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PROG
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(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))}
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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