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A023539
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Convolution of natural numbers with composite numbers.
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2
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4, 14, 32, 59, 96, 145, 208, 286, 380, 492, 624, 777, 952, 1151, 1375, 1625, 1902, 2207, 2542, 2909, 3309, 3743, 4212, 4717, 5260, 5842, 6464, 7128, 7836, 8589, 9388, 10235, 11131, 12077, 13074, 14123, 15226, 16384, 17598, 18869, 20198
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(1) = 1*4 = 4;
a(2) = 1*6 + 2*4 = 14;
a(3) = 1*8 + 2*6 + 3*4 = 32;
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PROG
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(PARI) lista(nn) = {my(vc = []); forcomposite(n=2, nn, vc = concat(vc, n); print1(sum(k=1, #vc, (#vc-k+1)*vc[k]), ", "); ); } \\ Michel Marcus, Feb 11 2018
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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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