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Search: id:A033196
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| A033196 |
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n^3*Product_{p|n} (1 + 1/p). |
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+0
3
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| 1, 12, 36, 96, 150, 432, 392, 768, 972, 1800, 1452, 3456, 2366, 4704, 5400, 6144, 5202, 11664, 7220, 14400, 14112, 17424, 12696, 27648, 18750, 28392, 26244, 37632, 25230, 64800, 30752, 49152, 52272, 62424, 58800, 93312, 52022, 86640
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
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Dirichlet g.f.: zeta(s-2)*zeta(s-3)/zeta(2*s-4).
Multiplicative with a(p^e) = p^e*p^(2*e-1)*(p+1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 16 2001
a(n)=sum_{d|n} mu(d)*sigma(n^3/d^2)=n^2*A001615(n) - Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 16 2008
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PROGRAM
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(PARI) a(n)=direuler(p=2, n, (1+p^2*X)/(1-p^3*X))[n]
(PARI) a(n)=sumdiv(n, d, moebius(d)*sigma(n^3/d^2)) - Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 16 2008
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CROSSREFS
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a(n)=n^2*A001615(n). Cf. A000082.
Sequence in context: A049598 A152135 A080562 this_sequence A060621 A058880 A055551
Adjacent sequences: A033193 A033194 A033195 this_sequence A033197 A033198 A033199
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KEYWORD
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nonn,easy,mult
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Additional comments from Michael Somos, May 19, 2000.
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