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Search: id:A135079
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| A135079 |
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E.g.f. A(x) = Sum_{n>=0} exp(3^n*x)*x^n/n!. |
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+0
3
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| 1, 2, 8, 56, 704, 15392, 593408, 39691136, 4650143744, 944100803072, 334651494268928, 205435333440321536, 219775256161359233024, 407034554694060677537792, 1312205966809501720566038528
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n) = Sum_{k=0..n} C(n, k)*3^(k*(n-k)).
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PROGRAM
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(PARI) {a(n)=sum(k=0, n, binomial(n, k)*3^(k*(n-k)))} (PARI) /* E.g.f.: */ {a(n)=n!*polcoeff(sum(k=0, n, exp(3^k*x +x*O(x^n))*x^k/k!), n)}
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CROSSREFS
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Cf. A047863 (variant).
Adjacent sequences: A135076 A135077 A135078 this_sequence A135080 A135081 A135082
Sequence in context: A005439 A128814 A108208 this_sequence A084872 A113725 A027335
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Nov 24 2007
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