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A051717 Denominators of Bernoulli twin numbers C(n). +0
7
1, 2, 3, 6, 30, 30, 42, 42, 30, 30, 66, 66, 2730, 2730, 6, 6, 510, 510, 798, 798, 330, 330, 138, 138, 2730, 2730, 6, 6, 870, 870, 14322, 14322, 510, 510, 6, 6, 1919190, 1919190, 6, 6, 13530, 13530, 1806, 1806, 690, 690, 282, 282, 46410, 46410, 66, 66, 1590, 1590 (list; graph; listen)
OFFSET

0,2

COMMENT

The Bernoulli twin numbers C(n) are defined by C(0) = 1, then C(2n) = B(2n)+B(2n-1), C(2n+1) = -B(2n+1)-B(2n), where B() are the Bernoulli numbers A027641/A027642. The definition is due to Paul Curtz.

Denominators of column 1 of table described in A051714/A051715.

LINKS

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

EXAMPLE

Sequence of C(n)'s begins: 1, -1/2, -1/3, -1/6, -1/30, 1/30, 1/42, -1/42, -1/30, 1/30, 5/66, -5/66, -691/2730, 691/2730, 7/6, -7/6, ...

MAPLE

C:=proc(n) if n=0 then RETURN(1); fi; if n mod 2 = 0 then RETURN(bernoulli(n)+bernoulli(n-1)); else RETURN(-bernoulli(n)-bernoulli(n-1)); fi; end;

CROSSREFS

Cf. A051716, A129825, A129826, A129724, A051714, A051715.

Sequence in context: A000341 A090445 A018318 this_sequence A108326 A002234 A074005

Adjacent sequences: A051714 A051715 A051716 this_sequence A051718 A051719 A051720

KEYWORD

nonn,easy,nice,frac

AUTHOR

njas

EXTENSIONS

More terms from James A. Sellers (sellersj(AT)math.psu.edu), Dec 08 1999

Edited by njas, May 25 2008

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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