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Search: id:A113327
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| 1, 2, 8, 36, 176, 928, 5296, 33024, 227776, 1757504, 15269888, 149327616, 1632715520, 19758502912, 261836047360, 3763432774656, 58208166178816, 962637398577152, 16934963591229440, 315578267054112768
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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G.f.: A(x) = 1/(1 - 2/1!*x*Sum(k>=0} (k+1)!*x^k ).
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EXAMPLE
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A(x) = (1 + 2*x + 8*x^2 + 36*x^3 + 176*x^4 + 928*x^5 +..) =
1/(1 - 2/1!*x*(1! + 2!*x + 3!*x^2 + 4!*x^3 + 5!*x^4 +..) ).
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PROGRAM
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(PARI) {a(n)=local(y=2, x=X+X*O(X^n)); polcoeff(1/(1 - y/(y-1)!*x*sum(k=0, n, (y-1+k)!*x^k)), n, X)}
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CROSSREFS
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Cf. A111146, A113326, A113328 (y=3), A113329 (y=4), A113330 (y=5), A113331 (y=6).
Sequence in context: A110837 A166229 A109318 this_sequence A129148 A081958 A001540
Adjacent sequences: A113324 A113325 A113326 this_sequence A113328 A113329 A113330
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KEYWORD
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nonn
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr) and Paul D. Hanna (pauldhanna(AT)juno.com), Oct 26 2005
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