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A141056 1 followed by A027760, a variant of Bernoulli number denominators. 16
1, 2, 6, 2, 30, 2, 42, 2, 30, 2, 66, 2, 2730, 2, 6, 2, 510, 2, 798, 2, 330, 2, 138, 2, 2730, 2, 6, 2, 870, 2, 14322, 2, 510, 2, 6, 2, 1919190, 2, 6, 2, 13530, 2, 1806, 2, 690, 2, 282, 2, 46410, 2, 66, 2, 1590, 2, 798, 2, 870, 2, 354, 2, 56786730, 2, 6, 2, 510, 2, 64722, 2, 30, 2, 4686 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

The denominators of the Bernoulli numbers for n>0. B_n sequence begins 1, -1/2, 1/6, 0/2, -1/30, 0/2, 1/42, 0/2, ... This is an alternative version of A027642 suggested by the theorem of Clausen. [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

LINKS

Thomas Clausen, Lehrsatz aus einer Abhandlung Ueber die Bernoullischen Zahlen, Astr. Nachr. 17 (22) (1840), 351-352. [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

Wikipedia, Bernoulli number [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

MAPLE

Contribution from Peter Luschny (peter(AT)luschny.de), Apr 29 2009: (Start)

Clausen := proc(n) local S, i;

S := numtheory[divisors](n); S := map(i->i+1, S);

S := select(isprime, S); mul(i, i=S) end proc:

seq(Clausen(i), i=0..24); (End)

CROSSREFS

Cf. A027760, A027642. [From Peter Luschny (peter(AT)luschny.de), Apr 29 2009]

Sequence in context: A131980 A076743 A027760 * A141498 A144845 A200563

Adjacent sequences:  A141053 A141054 A141055 * A141057 A141058 A141059

KEYWORD

nonn

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Aug 01 2008

EXTENSIONS

Extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 22 2009

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Last modified February 12 18:02 EST 2012. Contains 205432 sequences.