A141055 The n-th differences of the row A141045(n,.).

-1, -2, -60, -120, -5040, -10080, -302400, -604800, -39916800, -79833600, -217945728000, -435891456000, -2615348736000, -5230697472000, -2667655710720000, -5335311421440000, -4257578514309120000, -8515157028618240000, -2810001819444019200000

Offset

0,2

Comments

Can be thought of as the second sequence of a family: the first is A091137, the third starts 1, 2, 84, 168.

Links

Table of n, a(n) for n=0..18.

Formula

a(n+1) = a(n)*A027760(n+3).

Example

The first differences of A141045(2,.) are 11-(-19)=30 and -19-11 = -30. The 2nd difference is a(2)= -30-30= -60.

Mathematica

a[n_] := a[n] = a[n-1]*If[OddQ[n], 2, Denominator[BernoulliB[n+2]]]; a[0]=-1; Table[a[n], {n, 0, 18}] (* Jean-François Alcover, Dec 17 2014 *)

Prog

(PARI) a(n)=if(n, my(pr=a(n-1)); fordiv(n+2, d, if(isprime(d+1), pr*=d+1)); pr, -1) \\ Charles R Greathouse IV, Jul 08 2011

Crossrefs

Sequence in context: A354770 A087004 A328859 * A275819 A048541 A067739

Adjacent sequences: A141052 A141053 A141054 * A141056 A141057 A141058

Keyword

sign

Author

Paul Curtz, Aug 01 2008

Extensions

Edited and extended by R. J. Mathar, Aug 12 2008

Status

approved