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Search: id:A007322
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| A007322 |
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Number of functors of degree n from free abelian groups to abelian groups.
(Formerly M4231)
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+0
3
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| 1, 6, 39, 320, 3281, 40558, 586751, 9719616, 181353777, 3762893750, 85934344775, 2141853777856, 57852105131809, 1683237633305502, 52483648929669119, 1745835287515739328, 61712106494672572641, 2309989101145068446502
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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H. J. Baues, Quadratic functors and metastable homotopy, Jnl. Pure and Applied Algebra, 91 (1994), 49-107.
D. Zagier, personal communication.
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FORMULA
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Binomial transform of A101370. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 17 2006
a(n) = (1/n!)*Sum_{k=1..n} (-1)^(n-k)*Stirling1(n+1,k+1)*A000670(k)^2. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 17 2006
G.f.: (1/(1-x))*Sum_{m>0,n>0} Sum_{j=1..n} (-1)^(n-j)*binomial(n,j)*((1-x)^(-j)-1)^m. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 17 2006
Partial sums of A120733. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 21 2006
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CROSSREFS
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Adjacent sequences: A007319 A007320 A007321 this_sequence A007323 A007324 A007325
Sequence in context: A135890 A067273 A137972 this_sequence A058191 A113347 A031972
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KEYWORD
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nonn,nice
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AUTHOR
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njas, Mira Bernstein (mira(AT)math.berkeley.edu)
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Aug 17 2006
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