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A049211 a(n) = -product_{k = 0..n} (9*k - 1); 9-factorial numbers. 10
1, 8, 136, 3536, 123760, 5445440, 288608320, 17893715840, 1270453824640, 101636305971200, 9045631231436800, 886471860680806400, 94852489092846284800, 11002888734770169036800, 1375361091846271129600000, 184298386307400331366400000, 26354669241958247385395199999 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

FORMULA

a(n) = 8*A035022(n) = (9*n-1)(!^9), n >= 1, a(0) = 1.

a(n) = (-1)^n*sum_{k=0..n} 9^k*s(n+1,n+1-k), where s(n,k) are the Stirling numbers of the first kind, A048994. - Mircea Merca, May 03 2012

a(n) = 9^n * GAMMA(n+8/9) / GAMMA(8/9). - Vaclav Kotesovec, Jan 28 2015

E.g.f: (1-9*x)^(-8/9). - Vaclav Kotesovec, Jan 28 2015

MATHEMATICA

s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 7, 2*5!, 9}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 08 2008 *)

CoefficientList[Series[(1-9*x)^(-8/9), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 28 2015 *)

PROG

(PARI) a(n) = prod(k=1, n, 9*k-1); \\ Michel Marcus, Jan 08 2015

(MAGMA) [Floor(9^n * Gamma(n+8/9) / Gamma(8/9)): n in [0..20]]; // Vincenzo Librandi, Feb 21 2015

CROSSREFS

Cf. A008543, A049210, A049212.

Sequence in context: A132869 A036915 A238465 * A024283 A134053 A136472

Adjacent sequences:  A049208 A049209 A049210 * A049212 A049213 A049214

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

EXTENSIONS

a(9) (originally given incorrectly as 1011636305971200) corrected by Peter Bala, Feb 20 2015

a(15)-a(16) from Vincenzo Librandi, Feb 20 2015

STATUS

approved

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Last modified February 20 12:28 EST 2018. Contains 299379 sequences. (Running on oeis4.)