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A069267 a(n) = (2^(n-1)/(2n)!)*Product_{k=1..n} q(k) where q(n) is the denominator of B(2n), the 2n-th Bernoulli number. 0
3, 15, 42, 45, 66, 2730, 180, 765, 3990, 6930, 4140, 40950, 756, 1740, 57288, 58905, 630, 1919190, 16380, 284130, 595980, 434700, 118440, 4873050, 262548, 314820, 175560, 99180, 21240, 681440760, 2162160, 546975, 16504110, 217350, 421740 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Lim_{n->inf} a(n)^(1/n) = 1.

LINKS

Table of n, a(n) for n=1..35.

PROG

(PARI) a(n) = (2^(n-1)/(2*n)!)*prod(k=1, n, denominator(bernfrac(2*k))); \\ Michel Marcus, Jan 04 2021

CROSSREFS

Cf. A002445.

Sequence in context: A096742 A012256 A012222 * A059270 A219085 A093627

Adjacent sequences:  A069264 A069265 A069266 * A069268 A069269 A069270

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 14 2002

EXTENSIONS

Name edited by Michel Marcus, Jan 04 2021

STATUS

approved

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Last modified July 28 04:29 EDT 2021. Contains 346317 sequences. (Running on oeis4.)