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A046991 Denominators of Taylor series for log(1/cos(x)). Also from log(cos(x)). 3
1, 2, 12, 45, 2520, 14175, 935550, 42567525, 10216206000, 97692469875, 18561569276250, 2143861251406875, 34806217964017500, 48076088562799171875, 9086380738369043484375, 3952575621190533915703125, 3920955016221009644377500000, 68739242628124575327993046875 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

REFERENCES

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 88.

CRC Standard Mathematical Tables and Formulae, 30th ed. 1996, p. 42.

LINKS

T. D. Noe, Table of n, a(n) for n=0..100

Index entries for Bernoulli numbers B(2n)

FORMULA

A046990(n)/a(n)= 2^(2n-1) *(2^(2n) -1) *abs(B(2n)) / ((2n)! *n)

EXAMPLE

log(1/cos(x)) = 1/2*x^2+1/12*x^4+1/45*x^6+17/2520*x^8+31/14175*x^10+...

log(cos(x)) = -(1/2*x^2+1/12*x^4+1/45*x^6+17/2520*x^8+31/14175*x^10+...).

CROSSREFS

Cf. A046990, A046990, B(2n)= A027641(2n) / A027642(2n)

Sequence in context: A009074 A066258 A123771 * A188982 A061990 A006742

Adjacent sequences:  A046988 A046989 A046990 * A046992 A046993 A046994

KEYWORD

nonn,easy,frac,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 16 08:13 EST 2012. Contains 205893 sequences.