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A147626 Octo-factorial numbers(5). 1
1, 6, 84, 1848, 55440, 2106720, 96909120, 5233092480, 324451733760, 22711621363200, 1771506466329600, 152349556104345600, 14320858273808486400, 1460727543928465612800, 160680029832131217408000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..15.

FORMULA

a(n+1)=Sum_{k, 0<=k<=n}A132393(n,k)*6^k*8^(n-k). [From Philippe Deléham, Nov 09 2008]

a(n)=(-2)^n*sum_{k=0..n} 4^k*s(n+1,n+1-k), where s(n,k) are the Stirling numbers of the first kind, A048994. [From Mircea Merca, May 03 2012]

G.f.: 2*x/G(0), where G(k)= 1 + 1/(1 - 2*x*(8*k+6)/(2*x*(8*k+6) - 1 + 16*x*(k+1)/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 30 2013

MATHEMATICA

s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 5, 2*5!, 8}]; lst

CROSSREFS

Cf. A052714, A147625, A049210, A051189, A045755, A034908

Sequence in context: A128575 A322518 A014062 * A123312 A010794 A177560

Adjacent sequences:  A147623 A147624 A147625 * A147627 A147628 A147629

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Nov 08 2008

STATUS

approved

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Last modified March 26 18:36 EDT 2019. Contains 321511 sequences. (Running on oeis4.)