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A027642 Denominator of Bernoulli number B_n. +0
84
1, 2, 6, 1, 30, 1, 42, 1, 30, 1, 66, 1, 2730, 1, 6, 1, 510, 1, 798, 1, 330, 1, 138, 1, 2730, 1, 6, 1, 870, 1, 14322, 1, 510, 1, 6, 1, 1919190, 1, 6, 1, 13530, 1, 1806, 1, 690, 1, 282, 1, 46410, 1, 66, 1, 1590, 1, 798, 1, 870, 1, 354, 1, 56786730, 1 (list; graph; listen)
OFFSET

0,2

COMMENT

Row products of A138243. - Mats O. Granvik (mgranvik(AT)abo.fi), Mar 08 2008

Equals row products of triangle A143343 and for a(n)>1, row products of triangle A080092. [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 09 2008]

Julius Worpitzky's 1883 algorithm for generating Bernoulli numbers is described in A028246 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 09 2008]

The sequence of denominators of B_n is defined here by convention, not by necessity. The convention amounts to map 0 to the rational number 0/1. It might be more appropriate to regard numerators and denominators of the Bernoulli numbers as independent sequences N_n and D_n which combine to B_n = N_n / D_n. This is suggested by the theorem of Clausen which describes the denominators as the sequence D_n = 1, 2, 6, 2, 30, 2, 42,... which combines with N_n = 1, -1, 1, 0, -1, 0,... to the sequence of Bernoulli numbers. (Cf. A141056 and A027760.) [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

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. 810.

Clausen, Thomas, "Lehrsatz aus einer Abhandlung Ueber die Bernoullischen Zahlen", Astr. Nachr. 17 (1840), 351-352. [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 49.

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. 230.

Ghislain R. Franssens, On a Number Pyramid Related to the Binomial, Deleham, Eulerian, MacMahon and Stirling number triangles, Journal of Integer Sequences, Vol. 9 (2006), Article 06.4.1.

L. M. Milne-Thompson, Calculus of Finite Differences, 1951, p. 137.

Wikipedia (Bernoulli numbers) [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 09 2008]

LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000

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].

K.-W. Chen, Algorithms for Bernoulli numbers and Euler numbers, J. Integer Sequences, 4 (2001), #01.1.6.

M. Kaneko, The Akiyama-Tanigawa algorithm for Bernoulli numbers, J. Integer Sequences, 3 (2000), #00.2.9.

Hisanori Mishima, Factorizations of many number sequences

Hisanori Mishima, Factorizations of many number sequences

Hisanori Mishima, Factorizations of many number sequences

Index entries for sequences related to Bernoulli numbers.

Index entries for "core" sequences

FORMULA

E.g.f: x/(e^x - 1).

EXAMPLE

B_n sequence begins 1, -1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66, 0, -691/2730, 0, 7/6, 0, -3617/510, ...

MAPLE

(-1)^n*sum( (-1)^'m'*'m'!*stirling2(n, 'm')/('m'+1), 'm'=0..n);

with(numtheory):seq(denom(1-bernoulli(n+2)) , n=-2..59); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 08 2009]

with(numtheory):seq(denom(bernoulli(n)) , n=0..59); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 08 2009]

MATHEMATICA

Table[ Denominator[ BernoulliB[n]], {n, 0, 68}] (from Robert G. Wilson v Oct 11 2004)

Denominator[ Range[0, 68]! CoefficientList[ Series[x/(E^x - 1), {x, 0, 68}], x]]

PROGRAM

(PARI) a(n)=if(n<0, 0, denominator(bernfrac(n)))

CROSSREFS

See A027641 for full list of references, links, formulae, etc.

Cf. also A002882, A003245, A127187, A127188.

Cf. A138243.

Cf. A028246, A143343, A080092 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 09 2008]

Cf. A141056, A027760. [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

Sequence in context: A111519 A008855 A132181 this_sequence A117214 A134301 A004544

Adjacent sequences: A027639 A027640 A027641 this_sequence A027643 A027644 A027645

KEYWORD

nonn,frac,easy,core,nice

AUTHOR

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

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Last modified December 21 10:15 EST 2009. Contains 171081 sequences.


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