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A001897 Denominators of cosecant numbers -2*(2^(2*n-1)-1)*Bernoulli(2*n).
(Formerly M2983 N1205)
+0
5
1, 3, 15, 21, 15, 33, 1365, 3, 255, 399, 165, 69, 1365, 3, 435, 7161, 255, 3, 959595, 3, 6765, 903, 345, 141, 23205, 33, 795, 399, 435, 177, 28393365, 3, 255, 32361, 15, 2343, 70050435, 3, 15, 1659, 115005, 249, 1702155, 3, 30705, 136059, 705, 3, 2250885, 3, 16665, 2163 (list; graph; listen)
OFFSET

0,2

REFERENCES

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

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

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.

LINKS

N. E. Noerlund, Vorlesungen ueber Differenzenrechnung Springer 1924, p. 27.

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

EXAMPLE

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.

MAPLE

Contribution from Peter Luschny (peter(AT)luschny.de), May 02 2009: (Start)

b := n -> bernoulli(n)*2^add(i, i=convert(n, base, 2));

a := n -> denom(b(2*n)); (End)

CROSSREFS

Cf. A001896.

Cf. A132092-A132106.

Sequence in context: A083545 A097571 A048087 this_sequence A074214 A036897 A129966

Adjacent sequences: A001894 A001895 A001896 this_sequence A001898 A001899 A001900

KEYWORD

nonn

AUTHOR

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

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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