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A167368
a(n) = sigma((n!!)!).
2
1, 1, 3, 12, 159120, 6686252969760, 89050715142739003008099466232718435351438398888454549774336000
OFFSET
0,3
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
Sequence in context: A169815 A239891 A226129 * A318165 A215240 A068697
KEYWORD
nonn,less
AUTHOR
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Jan 12 2022
STATUS
approved