A167368 a(n) = sigma((n!!)!).

1, 1, 3, 12, 159120, 6686252969760, 89050715142739003008099466232718435351438398888454549774336000

Offset

0,3

Links

Table of n, a(n) for n=0..6.

Formula

a(n) = A000203(A161563(n)).

Mathematica

Array[DivisorSigma[1, #!!! ]&, 7, 1]

Prog

(PARI) A167368(n)=sigma( prod(k=0, n\2-1, n-2*k) ! )  \\ M. F. Hasler, Feb 07 2011

Crossrefs

Cf. A062569, A167367.

Sequence in context: A169815 A239891 A226129 * A318165 A215240 A068697

Adjacent sequences: A167365 A167366 A167367 * A167369 A167370 A167371

Keyword

nonn,less

Author

Vladimir Joseph Stephan Orlovsky, Nov 01 2009

Extensions

a(0)=1 prepended by Alois P. Heinz, Jan 12 2022

Status

approved