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A140351 Numerator of the coefficient [x^1] of the Bernoulli twin number polynomial C(n,x). 6
1, 0, -1, -1, -1, 1, 1, -1, -3, 3, 5, -5, -691, 691, 35, -35, -3617, 3617, 43867, -43867, -1222277, 1222277, 854513, -854513, -1181820455, 1181820455, 76977927, -76977927, -23749461029, 23749461029, 8615841276005, -8615841276005, -84802531453387, 84802531453387 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

COMMENTS

The Bernoulli twin number polynomials C(n,x) are defined in A129378.

I call the full fraction [x^1]C(n,x) the secondary Bernoulli twin numbers.

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

The coefficients [x^m]C(n,x) are a table of fractions:

1 ;

-1/2, 1;

-1/3, 0, 1;

-1/6, -1/2, 1/2, 1;

-1/30,-1/2, -1/2, 1, 1;

1/30, -1/6, -1,-1/3, 3/2, 1;

1/42, 1/6, -1/2, -5/3, 0, 2, 1;

-1/42, 1/6, 1/2, -7/6, -5/2, 1/2, 5/2, 1;

-1/30, -1/6, 2/3, 7/6, -7/3, -7/2, 7/6, 3, 1;

1/30, -3/10, -2/3, 2, 7/3, -21/5, -14/3, 2, 7/2, 1;

5/66, 3/10, -3/2, -2, 5, 21/5, -7, -6, 3, 4, 1; ...

This sequence here contains the numerators of the second column.

MAPLE

C := proc(n, x) if n = 0 then 1; else add(binomial(n-1, j-1)* bernoulli(j, x), j=1..n) ; expand(%) ; end if ; end proc:

A140351 := proc(n) coeff(C(n, x), x, 1) ; numer(%) ; end proc: seq(A140351(n), n=1..80) ; # R. J. Mathar, Nov 22 2009

MATHEMATICA

b[n_, x_] := Coefficient[ Series[ t*E^(x*t)/(E^t - 1), {t, 0, n}], t, n]*n!; c[n_, x_] := Sum[ Binomial[n-1, j-1]*b[j, x], {j, 1, n}]; t[n_, m_] := Coefficient[c[n, x], x, m]; Table[t[n, 1] // Numerator, {n, 1, 34} ] (* Jean-Fran├žois Alcover, Mar 04 2013 *)

CROSSREFS

Cf. A129826

Sequence in context: A014414 A087745 A087756 * A128444 A204250 A131948

Adjacent sequences:  A140348 A140349 A140350 * A140352 A140353 A140354

KEYWORD

frac,sign

AUTHOR

Paul Curtz, May 30 2008, Jun 23 2008

EXTENSIONS

Edited and extended by R. J. Mathar, Nov 22 2009

STATUS

approved

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Last modified April 23 05:30 EDT 2014. Contains 240913 sequences.