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A144829 Partial products of successive terms of A017209; a(0)=1 . 4
1, 4, 52, 1144, 35464, 1418560, 69509440, 4031547520, 270113683840, 20528639971840, 1744934397606400, 164023833375001600, 16894454837625164800, 1892178941814018457600, 228953651959496233369600, 29763974754734510338048000, 4137192490908096936988672000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

a(n) = Sum_{k=0..n} A132393(n,k)*4^k*9^(n-k).

a(n) = (-5)^n*Sum_{k=0..n} (9/5)^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+5)*a(n-1)=0. - R. J. Mathar, Sep 04 2016

EXAMPLE

a(0)=1, a(1)=4, a(2)=4*13=52, a(3)=4*13*22=1144, a(4)=4*13*22*31=35464, ...

MATHEMATICA

s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 3, 2*5!, 9}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 08 2008 *)

PROG

(PARI) a(n) = (-5)^n*sum(k=0, n, (9/5)^k*stirling(n+1, n+1-k, 1)); \\ Michel Marcus, Feb 20 2015

CROSSREFS

Cf. A001715, A002866, A007559, A047053, A008546, A049308, A144827, A144828.

Sequence in context: A247020 A059580 A091463 * A287699 A280571 A277353

Adjacent sequences:  A144826 A144827 A144828 * A144830 A144831 A144832

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Sep 21 2008

EXTENSIONS

a(9) originally given incorrectly as 20520639971840 corrected by Peter Bala, Feb 20 2015

STATUS

approved

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Last modified February 20 17:04 EST 2020. Contains 332080 sequences. (Running on oeis4.)