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Search: id:A118795
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A118795 E.g.f.: -1 + exp(( 1 - sqrt(5 - 4*exp(x)) )/2). +0
3
0, 1, 4, 29, 329, 5172, 104335, 2571473, 74894818, 2516911731, 95862252417, 4080739041238, 192000366357981, 9894168501171229, 554208686184384028, 33527021385789228265, 2178482569432714859789, 151314182463701892157460 (list; graph; listen)
OFFSET

0,3

COMMENT

Also equals the unsigned row sums of triangle A118793 (offset without leading zero).

FORMULA

a(n) = (n-1)!*Sum_{k=0..n-1} abs( [x^k] (x/log(1-x-x^2))^n/(n-1-k)! ) for n>0.

EXAMPLE

E.g.f.: A(x) = x + 4/2*x^2 + 29/6*x^3 + 329/24*x^4 + 5172/120*x^5 +...

PROGRAM

(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 unsigned 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, abs(polcoeff(((x/log(1-x-x^2)))^n/(n-1-k)!, k, X))))}

CROSSREFS

Cf. A118793, A118794.

Sequence in context: A067146 A030019 A028853 this_sequence A099700 A137646 A000798

Adjacent sequences: A118792 A118793 A118794 this_sequence A118796 A118797 A118798

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Apr 30 2006

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.


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