A034909 - OEIS

A034909

One third of octo-factorial numbers.

1, 11, 209, 5643, 197505, 8492715, 433128465, 25554579435, 1712156822145, 128411761660875, 10658176217852625, 969894035824588875, 96019509546634298625, 10274087521489869952875, 1181520064971335044580625, 145326967991474210483416875, 19037832806883121573327610625

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

Index entries for sequences related to factorial numbers.

FORMULA

3*a(n) = (8*n-5)(!^8) = product(8*j-5, j=1..n).

E.g.f.: (-1+(1-8*x)^(-3/8))/3.

G.f.: x/(1-11x/(1-8x/(1-19x/(1-16x/(1-27x/(1-24x/(1-35x/(1-32x/(1-... (continued fraction). - Philippe Deléham, Jan 07 2012

From Amiram Eldar, Dec 20 2022: (Start)

a(n) = A144756(n)/3.