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A036278 Denominators in Taylor series for cot x. +0
3
1, 3, 45, 945, 4725, 93555, 638512875, 18243225, 162820783125, 38979295480125, 1531329465290625, 13447856940643125, 201919571963756521875, 11094481976030578125, 564653660170076273671875, 5660878804669082674070015625, 31245110285511170603633203125 (list; graph; listen)
OFFSET

-1,2

REFERENCES

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 75 (4.3.70).

G. W. Caunt, Infinitesimal Calculus, Oxford Univ. Press, 1914, p. 477.

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

H. Rademacher, Topics in Analytic Number Theory, Springer, 1973, Chap. 1, p. 19.

LINKS

T. D. Noe, Table of n, a(n) for n=-1..100

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 75 (4.3.70).

Eric Weisstein's World of Mathematics, Cotangent

FORMULA

cot x = Sum_{k=0..inf} (-1)^k B_{2k} 4^k x^(2k-1) / (2k)!.

a(n)=denominator(A000182[ n ]/(4^n-1)), n>0.

EXAMPLE

x^(-1)-1/3*x-1/45*x^3-2/945*x^5-1/4725*x^7-2/93555*x^9+O(x^11).

CROSSREFS

Cf. A002431 (numerators).

Sequence in context: A124487 A132303 A008931 this_sequence A154289 A012827 A012769

Adjacent sequences: A036275 A036276 A036277 this_sequence A036279 A036280 A036281

KEYWORD

nonn,frac,easy,nice

AUTHOR

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

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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