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Search: id:A118792
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| A118792 |
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E.g.f.: -log(1 - (1 - sqrt(5 - 4*exp(x)) )/2 ). |
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+0
2
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| 0, 1, 4, 30, 352, 5670, 116344, 2902830, 85326112, 2887962870, 110620824904, 4730842053630, 223445584599472, 11552029520192070, 648869447924011864, 39347855472366932430, 2562065820090343738432, 178286102174571726213270
(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 unsigned row sums of triangle A118791 (offset without leading zero).
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FORMULA
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a(n) = (n-1)!*Sum_{k=0..n-1} abs( [x^k] (x/log(1-x-x^2))^n ) for n>0.
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EXAMPLE
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E.g.f.: A(x) = x + 2*x^2 + 30/6*x^3 + 352/24*x^4 + 5670/120*x^5 +...
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PROGRAM
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(PARI) {a(n)=local(x=X+X^2*O(X^n)); n!*polcoeff(-log(1-(1-sqrt(5-4*exp(x)))/2), n, X)} (PARI) /* As the unsigned row sums of A118791: */ {a(n)=local(x=X+X^2*O(X^n)); if(n<1, 0, (n-1)!*sum(k=0, n-1, abs(polcoeff(((-x/log(1-x-x^2)))^n, k, X))))}
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CROSSREFS
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Cf. A118791.
Sequence in context: A052316 A089918 A132622 this_sequence A137341 A120338 A064050
Adjacent sequences: A118789 A118790 A118791 this_sequence A118793 A118794 A118795
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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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