A167367 a(n) = sigma(n!!) where n!! is A006882(n).

1, 1, 3, 4, 15, 24, 124, 192, 1020, 1920, 12264, 23040, 159666, 322560, 2555280, 5041344, 40893840, 90744192, 761260368, 1814883840, 15732804296, 38900010240, 377587663200, 933600245760, 9087075973248, 23520702965760, 254438142416640

Offset: 0

Author

Vladimir Joseph Stephan Orlovsky, Nov 01 2009

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..500

Crossrefs

Cf. A062569.

Programs

Mathematica

Join[{1},Array[DivisorSigma[1,#!! ]&,50,1]]

PARI

a(n)=sigma(prod(i=0, (n-1)\2, n - 2*i )) \\ Charles R Greathouse IV, May 01 2016

Formula

a(n) = A000203(A006882(n)). - R. J. Mathar, Feb 07 2011