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A002427 Numerator of (2n+1) B_{2n}, where B_n are the Bernoulli numbers.
(Formerly M2510 N0993)
4
1, 1, -1, 1, -3, 5, -691, 35, -3617, 43867, -1222277, 854513, -1181820455, 76977927, -23749461029, 8615841276005, -84802531453387, 90219075042845, -26315271553053477373, 38089920879940267, -261082718496449122051, 1520097643918070802691 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Doubled a(n+2)=-1,1,-3,5,-691,35, "gives" A140351(n+4) secondary Bernoulli twin numbers.Thanks to R. J. Mathar. [From Paul Curtz, Nov 28 2009]

REFERENCES

L. Euler, (E393) De summis serierum numeros Bernoullianos involventium, reprinted in: Opera Omnia. Teubner, Leipzig, 1911, Series (1), Vol. 15, p. 93.

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 73.

M. Kaneko, "A recurrence formula for the Bernoulli numbers", Proc. Japan Acad., 71 A (1995), 192-193.

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

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

Index entries for sequences related to Bernoulli numbers.

EXAMPLE

(n+1)*B_n gives the sequence 1, -1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66, ...

MATHEMATICA

Numerator[ Table[2(2n + 1)BernoulliB[2n], {n, 1, 21}]]

CROSSREFS

Denominators are in A006955. Cf. A050925/A050932, A000367/A002445.

Sequence in context: A087368 A087670 A138584 * A136134 A119497 A012783

Adjacent sequences:  A002424 A002425 A002426 * A002428 A002429 A002430

KEYWORD

sign,easy,nice,frac

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified June 18 19:42 EDT 2013. Contains 226356 sequences.