A034909 One third of octo-factorial numbers.

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

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.

Sum_{n>=1} 1/a(n) = 3*(e/8^5)^(1/8)*(Gamma(3/8) - Gamma(3/8, 1/8)). (End)

Crossrefs

Cf. A045755, A034908, A034909, A034910, A034911, A034912, A144756.

Sequence in context: A196849 A196699 A131216 * A081788 A358321 A060496

Adjacent sequences: A034906 A034907 A034908 * A034910 A034911 A034912

Keyword

easy,nonn

Author

Wolfdieter Lang

Status

approved