A145610 Denominator of the polynomial A_l(x) = Sum_{d=1..l-1} x^(l-d)/d for index l=2n+1 evaluated at x=1.

2, 12, 20, 280, 2520, 27720, 360360, 720720, 4084080, 15519504, 5173168, 356948592, 8923714800, 80313433200, 2329089562800, 144403552893600, 13127595717600, 13127595717600, 485721041551200, 485721041551200

Offset: 1

Author

Artur Jasinski, Oct 14 2008

Keywords

• frac
• nonn

Comments

For numerators and explicit examples of the polynomials see A145609.

Crossrefs

Cf. A145609 - A145640.

Programs

Maple

A := proc(l,x) add(x^(l-d)/d,d=1..l-1) ; end: A145610 := proc(n) denom( A(2*n+1,1)) ; end: seq(A145610(n),n=1..20) ; # R. J. Mathar, Aug 21 2009

Mathematica

m = 1; aa = {}; Do[k = 0; Do[k = k + m^(2 r + 1 - d)/d, {d, 1, 2 r}]; AppendTo[aa, Denominator[k]], {r, 1, 30}]; aa (* Artur Jasinski *)

Extensions

Edited by R. J. Mathar, Aug 21 2009