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Search: id:A118794
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| A118794 |
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E.g.f.: 1 - exp((-1 + sqrt(5 - 4*exp(x)) )/2). |
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+0
3
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| 0, 1, 2, 11, 121, 1902, 38381, 945989, 27552260, 925920081, 35265751869, 1501219998148, 70632987480771, 3639861179067661, 203881981765871618, 12333901891547136559, 801418950244634922973, 55665376886060309513990
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Also equals the row sums of triangle A118793 (offset without leading zero).
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FORMULA
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a(n) = (n-1)!*Sum_{k=0..n-1} [x^k] (x/log(1-x-x^2))^n/(n-1-k)! for n>0.
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EXAMPLE
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E.g.f.: A(x) = x + 2/2*x^2 + 11/6*x^3 + 121/24*x^4 + 1902/120*x^5 +...
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PROGRAM
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(PARI) {a(n)=local(x=X+X^2*O(X^n)); n!*polcoeff(1-exp((-1+sqrt(5-4*exp(x)))/2), n, X)} (PARI) /* As the row sums of A118793: */ {a(n)=local(x=X+X^2*O(X^n)); if(n<1, 0, -(n-1)!*sum(k=0, n-1, polcoeff(((x/log(1-x-x^2)))^n/(n-1-k)!, k, X)))}
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CROSSREFS
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Cf. A118793, A118795.
Sequence in context: A090534 A130222 A057076 this_sequence A001946 A112864 A077391
Adjacent sequences: A118791 A118792 A118793 this_sequence A118795 A118796 A118797
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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), Apr 30 2006
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