A142048 Triangle of the denominators of the coefficients [x^k] P(n,x) defined in A141904.

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

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-François Alcover, Oct 02 2012 *)

Crossrefs

Cf. A141904 (numerators).

Sequence in context: A122510 A102662 A350279 * 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