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Search: id:A135743
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| A135743 |
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E.g.f.: A(x) = Sum_{n>=0} exp(n*(n+1)/2*x)*x^n/n!. |
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+0
6
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| 1, 1, 3, 13, 83, 686, 7132, 90343, 1357449, 23783068, 478784096, 10938189329, 280771780489, 8029138915630, 253911056912892, 8823070442039641, 335009138739028673, 13830540214264709000, 618085473234055115968
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OFFSET
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0,3
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FORMULA
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a(n) = Sum_{k=0..n} C(n,k)*[k*(k+1)/2]^(n-k).
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PROGRAM
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(PARI) {a(n)=sum(k=0, n, binomial(n, k)*(k*(k+1)/2)^(n-k))} (PARI) {a(n)=n!*polcoeff(sum(k=0, n, exp(k*(k+1)/2*x +x*O(x^n))*x^k/k!), n)}
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CROSSREFS
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Cf. variants: A135742, A135744, A135745, A135746.
Adjacent sequences: A135740 A135741 A135742 this_sequence A135744 A135745 A135746
Sequence in context: A000684 A057993 A000904 this_sequence A123114 A104032 A130406
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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 27 2007
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