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A001896 Numerators of cosecant numbers -2*(2^(2*n-1)-1)*Bernoulli(2*n); also of Bernoulli(2n,1/2) and Bernoulli(2n,1/4).
(Formerly M4403 N1858)
6
1, -1, 7, -31, 127, -2555, 1414477, -57337, 118518239, -5749691557, 91546277357, -1792042792463, 1982765468311237, -286994504449393, 3187598676787461083, -4625594554880206790555, 16555640865486520478399, -22142170099387402072897 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

Cosecant number are given by the integral: (-Pi^2)^(-n)*int((ln(x/(1-x)))^2*n,x=0..1) [From Groux roland (roland.groux(AT)orange.fr), Nov 10 2009]

REFERENCES

H. T. Davis, Tables of the Mathematical Functions. Vols. 1 and 2, 2nd ed., 1963, Vol. 3 (with V. J. Fisher), 1962; Principia Press of Trinity Univ., San Antonio, TX, Vol. 2, p. 187.

S. A. Joffe, Sums of like powers of natural numbers, Quart. J. Pure Appl. Math. 46 (1914), 33-51.

D. H. Lehmer, Lacunary recurrence formulas for the numbers of Bernoulli and Euler, Annals Math., 36 (1935), 637-649.

N. E. N\"{o}rlund, Vorlesungen \"{u}ber Differenzenrechnung. Springer-Verlag, Berlin, 1924, p. 458.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Hector Blandin and Rafael Diaz, Compositional Bernoulli numbers, Page 7, 3rd table, (B^sin)_1,n is identical to |A001896| / A001897.

Index entries for sequences related to Bernoulli numbers.

FORMULA

with(numtheory); [ seq(bernoulli(2*n, 1/2), n=0..20) ];

EXAMPLE

1, -1/12, 7/240, -31/1344, 127/3840, -2555/33792, 1414477/5591040, -57337/49152, 118518239/16711680, ... = A001896/A033469

Cosecant numbers -2*(2^(2*n-1)-1)*Bernoulli(2*n) are 1, -1/3, 7/15, -31/21, 127/15, -2555/33, 1414477/1365, -57337/3, 118518239/255, -5749691557/399, 91546277357/165, -1792042792463/69, 1982765468311237/1365, -286994504449393/3, 3187598676787461083/435, ... = A001896/A001897.

CROSSREFS

Cf. A001897, A033469, A132092-A132106.

Sequence in context: A083420 A036282 A033474 * A180147 A044049 A005825

Adjacent sequences:  A001893 A001894 A001895 * A001897 A001898 A001899

KEYWORD

sign,frac

AUTHOR

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

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.