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A002790 Denominators of Cauchy numbers of second type (= Bernoulli numbers B_n^{(n)}).
(Formerly M1559 N0608)
11
1, 2, 6, 4, 30, 12, 84, 24, 90, 20, 132, 24, 5460, 840, 360, 16, 1530, 180, 7980, 840, 13860, 440, 1656, 720, 81900, 6552, 216, 112, 3480, 240, 114576, 7392, 117810, 2380, 1260, 72, 3838380, 207480, 32760, 560, 568260, 27720, 238392, 55440, 869400, 2576, 236880 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

These coefficients (with alternating signs) are also known as the Nørlund [or Norlund or Noerlund] numbers.

REFERENCES

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 294.

L. M. Milne-Thompson, Calculus of Finite Differences, 1951, p. 136.

Guodong Liu, Some computational formulas for Norlund numbers, Fib. Quart., 45 (2007), 133-137.

Merlini, Donatella; Sprugnoli, Renzo; and Verri, M. Cecilia; The Cauchy numbers. Discrete Math. 306 (2006), no. 16, 1906-1920.

N. E. Nørlund, Vorlesungen ueber Differenzenrechnung, Springer-Verlag, Berlin, 1924.

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).

Feng-Zhen Zhao, Sums of products of Cauchy numbers, Discrete Math., 309 (2009), 3830-3842.

LINKS

T. D. Noe, Table of n, a(n) for n=0..1000

Index entries for sequences related to Bernoulli numbers.

FORMULA

Denominator of integral of x(x+1)...(x+n-1) from 0 to 1.

E.g.f.: -x/(1-x)/ln(1-x).

Denominator of Sum_{k=0..n} (-1)^k A008275(n,k)/(k+1). [From Peter Luschny (peter(AT)luschny.de), Apr 28 2009]

a(n) = A091137(n)/n!. [From Paul Curtz (bpcrtz(AT)free.fr), Nov 27 2008]

EXAMPLE

1, 1/2, 5/6, 9/4, 251/30, 475/12, 19087/84, 36799/24, 1070017/90, ...

MAPLE

seq(denom(add((-1)^k*stirling1(n, k)/(k+1), k=0..n)), n=0..20); [From Peter Luschny (peter(AT)luschny.de), Apr 28 2009]

MATHEMATICA

Table[ Denominator[ NorlundB[n, n]], {n, 0, 60}] (* From Vladimir Joseph Stephan Orlovsky (4vladimir(AT)gmail.com), 30 Dec 2010 *)

CROSSREFS

Cf. A002657. See also A002208, A002209, A002206, A002207, A006232, A006233.

Sequence in context: A057643 A073039 A064538 * A108951 A181822 A174940

Adjacent sequences:  A002787 A002788 A002789 * A002791 A002792 A002793

KEYWORD

nonn,frac,nice,easy

AUTHOR

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

EXTENSIONS

Improved readability of the Curtz formula - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 17 2010

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Last modified February 16 19:06 EST 2012. Contains 205945 sequences.