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A086666
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sigma_2(n)-sigma(n).
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0
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0, 2, 6, 14, 20, 38, 42, 70, 78, 112, 110, 182, 156, 226, 236, 310, 272, 416, 342, 504, 468, 574, 506, 790, 620, 808, 780, 994, 812, 1228, 930, 1302, 1172, 1396, 1252, 1820, 1332, 1750, 1644, 2120, 1640, 2404, 1806, 2478, 2288, 2578, 2162, 3286, 2394, 3162
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..50.
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FORMULA
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G.f.: sum(n>=1, n*(n-1) * x^n/(1-x^n) ). - Joerg Arndt, Jan 30, 2011
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PROG
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(PARI) for (n=2, 50, print1(sigma(n, 2)-sigma(n, 1)", "))
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CROSSREFS
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Cf. A000203, A001157.
Sequence in context: A107369 A151731 A009779 * A032383 A014775 A009218
Adjacent sequences: A086663 A086664 A086665 * A086667 A086668 A086669
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KEYWORD
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nonn
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AUTHOR
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Jon Perry, Jul 27 2003
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STATUS
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approved
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