A053023 Divisor function applied thrice to n!.

1, 2, 2, 3, 2, 4, 6, 6, 6, 5, 8, 8, 8, 8, 8, 9, 8, 10, 8, 10, 10, 12, 10, 10, 10, 15, 16, 16, 18, 16, 8, 16, 10, 12, 16, 18, 14, 3, 14, 16, 24, 16, 16, 20, 24, 24, 28, 24, 24, 16, 24, 24, 32, 32, 28, 32, 18, 20, 24, 28, 36, 32, 36, 24, 21, 24, 20, 40, 40, 30, 30, 36, 40, 42, 24, 32

Offset

1,2

Links

Table of n, a(n) for n=1..76.

Formula

d[ d[ d[ n! ] ] ] = A036450(A000142(n)) = A036450(n!)

Example

A036450[x]=8 if x = 11!, 12!, 13!, 14!, 15!. The reversed sequences of these d-iterates are {2, 3, 4, 8, 24, 540, 39916800}, {2, 3, 4, 8, 24, 792, 479001600}, {2, 3, 4, 8, 30, 1584, 6227020800}, {2, 3, 4, 8, 30, 2592, 87178291200}, {2, 3, 4, 8, 42, 4032, 1307674368000}.

Crossrefs

Cf. A000005, A027473, A010553, A036450, A000142.

Sequence in context: A239471 A241509 A268327 * A153725 A102247 A054249

Adjacent sequences: A053020 A053021 A053022 * A053024 A053025 A053026

Keyword

nonn

Author

Labos Elemer, Feb 24 2000

Status

approved