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A090753 Coefficients of power series A(x) such that n-th term of A(x)^n = n!*n*x^(n-1), for n>0. 3
1, 2, 2, 4, 16, 88, 600, 4800, 43680, 443296, 4949920, 60217408, 792134528, 11200176128, 169375195136, 2728019576832, 46626359376384, 842947307334144, 16073131554826752, 322403473258650624, 6786861273524305920 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

At n=4 the 4th term of A(x)^4 is 4!*4x^3 = 96*x^3, as demonstrated by A(x)^4 = 1 + 8*x + 32*x^2 + 96*x^3 + 296*x^4 + ... See also A075834.

LINKS

Table of n, a(n) for n=0..20.

FORMULA

a(n) = Sum_{j=2..(n-2)} (j-1)*a(j)*a(n-j) for n>=2, with a(0)=1, a(1)=2.

Sum_{j>=0} a(j)*A090238(n-1, k+j-1) = A090238(n, k).

G.f. satisfies: A(x) = 1 + 2*Sum_{n>=1} n^n * x^n / (A(x) + n*x)^n. - Paul D. Hanna, Feb 04 2013

PROG

(PARI) a(n)=if(n<0, 0, polcoeff(x/serreverse(sum(k=1, n+1, k!*x^k, x^2*O(x^n))), n)) /* Michael Somos, Feb 14 2004 */

(PARI) a(n)=local(A=1+x); for(i=1, n, A=1+2*sum(m=1, n, m^m*x^m/(A+m*x+x*O(x^n))^m)); polcoeff(A, n)

for(n=0, 30, print1(a(n), ", ")) \\ Paul D. Hanna, Feb 04 2013

CROSSREFS

Cf. A075834, A211207, A136633.

Sequence in context: A009542 A244108 A032318 * A091788 A063401 A168088

Adjacent sequences:  A090750 A090751 A090752 * A090754 A090755 A090756

KEYWORD

nonn

AUTHOR

Philippe Deléham, Feb 06 2004

STATUS

approved

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Last modified August 8 19:29 EDT 2020. Contains 336298 sequences. (Running on oeis4.)