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A006953 Denominator of Bernoulli(2*n)/(2*n).
(Formerly M2039)
5
12, 120, 252, 240, 132, 32760, 12, 8160, 14364, 6600, 276, 65520, 12, 3480, 85932, 16320, 12, 69090840, 12, 541200, 75852, 2760, 564, 2227680, 132, 6360, 43092, 6960, 708, 3407203800, 12, 32640, 388332, 120, 9372, 10087262640 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

a(n) is divible by period 2 repeat 12, 120. A141590/(2 before a(n+1) =1/2 + 1/12 -1/120 + 1/252 is an old Euler's formula for gamma A001620. Also sum (from 0 to infinity) B(2*n)/(2*A028310(n)). - Paul Curtz, Sep 13 2011

REFERENCES

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 259, (6.3.18) and (6.3.19); also p. 810.

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

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

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. 259, (6.3.18) and (6.3.19).

G. Everest, A. J. van der Poorten, Y. Puri and T. Ward, Integer Sequences and Periodic Points, Journal of Integer Sequences, Vol. 5 (2002), Article 02.2.3

E. Z. Goren, Tables of values of Riemann zeta functions

Y. Puri and T. Ward, Arithmetic and growth of periodic orbits, J. Integer Seqs., Vol. 4 (2001), #01.2.1.

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Eric Weisstein's World of Mathematics, Harmonic Number

Index entries for sequences related to Bernoulli numbers.

FORMULA

Zeta(1-2n) = - Bernoulli(2n)/(2n).

G.f. for Bernoulli(2*n)/(2*n) = A001067(n)/A006953(n): (-1)^n/((2*Pi)^(2*n)*(2*n))*integral(log(1-1/t)^(2*n) dt,t=0,1) - [Gerry Martens, May 18 2011]

EXAMPLE

Sequence Bernoulli(2n)/(2n) (n >= 1) begins 1/12, -1/120, 1/252, -1/240, 1/132, -691/32760, 1/12, -3617/8160, ...

MATHEMATICA

a[n_]:=Denominator[BernoulliB[2*n]/(2*n)]; [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 13 2008]

CROSSREFS

Numerators given by A001067.

Sequence in context: A075366 A076633 A110423 * A164877 A121032 A188251

Adjacent sequences:  A006950 A006951 A006952 * A006954 A006955 A006956

KEYWORD

nonn,frac,easy,nice

AUTHOR

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

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.