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A289488 a(n) = denominator of Sum_{k=1..n} 1/(2*k-1)!!. 2
1, 3, 5, 105, 945, 3465, 135135, 2027025, 883575, 654729075, 13749310575, 8108567775, 718713961875, 213458046676875, 121378104973125, 191898783962510625, 372509404162520625, 73881031825566590625, 8200794532637891559375, 319830986772877770815625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..404

OEIS Wiki, A remarkable formula of Ramanujan

EXAMPLE

1, 4/3, 7/5, 148/105, 1333/945, 4888/3465, 190633/135135, 2859496/2027025, 1246447/883575, 923617228/654729075, 19395961789/13749310575, 11438644132/8108567775, ... = A289381(n)/a(n) -> A060196.

CROSSREFS

Cf. A001147, A060196, A289381.

Sequence in context: A234600 A003112 A130187 * A054266 A054268 A153137

Adjacent sequences:  A289485 A289486 A289487 * A289489 A289490 A289491

KEYWORD

nonn,frac

AUTHOR

Seiichi Manyama, Sep 02 2017

STATUS

approved

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Last modified January 17 18:48 EST 2019. Contains 319251 sequences. (Running on oeis4.)