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A142048 Triangle of the denominators of the coefficients [x^k] P(n,x) defined in A141904. 4
1, 3, 1, 5, 3, 1, 7, 45, 1, 1, 9, 105, 15, 3, 1, 11, 1575, 945, 15, 3, 1, 13, 10395, 175, 945, 9, 1, 1, 15, 315315, 17325, 14175, 189, 15, 3, 1, 17, 45045, 23648625, 7425, 2835, 189, 15, 3, 1, 19, 6891885, 1576575, 23648625, 93555, 945, 135, 45, 1, 1, 21, 72747675, 7309575 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Are all the denominators odd?

LINKS

Table of n, a(n) for n=0..57.

MATHEMATICA

ClearAll[u, p]; u[n_] := (-1)^n/(2*n + 1); p[0][x_] := u[0]; p[n_][x_] := p[n][x] = u[n] + x*Sum[u[i]*p[n - i - 1][x] , {i, 0, n-1}] // Expand; row[n_] := CoefficientList[ p[n][x], x]; Table[row[n], {n, 0, 10}] // Flatten // Denominator (* Jean-Fran├žois Alcover, Oct 02 2012 *)

CROSSREFS

Cf. A141904 (numerators).

Sequence in context: A159291 A122510 A102662 * A117563 A060439 A206283

Adjacent sequences:  A142045 A142046 A142047 * A142049 A142050 A142051

KEYWORD

nonn,frac,tabl

AUTHOR

Paul Curtz, Sep 14 2008

EXTENSIONS

Edited and extended by R. J. Mathar, Aug 24 2009

STATUS

approved

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Last modified June 26 00:41 EDT 2019. Contains 324367 sequences. (Running on oeis4.)