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A134528 G.f. A(x) satisfies: 1 = Sum_{n>=0} A(x)^(n+1)*x^n/2^(n*(n-1)/2) where A(x) = Sum_{n>=0} a(n)*x^n/2^(n*(n-1)/2). 0
1, -1, 3, -21, 319, -10193, 674047, -91369921, 25234490623, -14140806673665, 16031563354478591, -36691986271455923201, 169262051631703928107007, -1571807846118598776606101505, 29353752424684301883376834576383, -1101562988034649825668233119938625537 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..15.

FORMULA

G.f.: A(x) = (1/x)*series_reversion[x*Sum_{n>=0} x^n/2^(n*(n-1)/2)].

EXAMPLE

A(x) = 1 - x + 3/2*x^2 - 21/8*x^3 + 319/64*x^4 - 10193/1024*x^5 +...

1 = A(x) + A(x)^2*x + A(x)^3*x^2/2 + A(x)^4*x^3/8 + A(x)^5*x^4/64 + ...

PROG

(PARI) {a(n)=2^(n*(n+1)/2)*polcoeff((1/x)*serreverse(sum(k=1, n+1, x^k/2^(k*(k-1)/2))+O(x^(n+2))), n)}

CROSSREFS

Cf. A118410.

Sequence in context: A305532 A005329 A341471 * A332974 A118410 A125054

Adjacent sequences:  A134525 A134526 A134527 * A134529 A134530 A134531

KEYWORD

sign

AUTHOR

Paul D. Hanna, Nov 23 2007

STATUS

approved

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Last modified September 20 22:12 EDT 2021. Contains 347594 sequences. (Running on oeis4.)