A336418 Numbers with a factorial number of divisors.

1, 2, 3, 5, 7, 11, 12, 13, 17, 18, 19, 20, 23, 28, 29, 31, 32, 37, 41, 43, 44, 45, 47, 50, 52, 53, 59, 61, 63, 67, 68, 71, 73, 75, 76, 79, 83, 89, 92, 97, 98, 99, 101, 103, 107, 109, 113, 116, 117, 124, 127, 131, 137, 139, 147, 148, 149, 151, 153, 157, 163

Offset

1,2

Comments

Positive integers n such that A000005(n) belongs to A000142.

Links

Table of n, a(n) for n=1..61.

Mathematica

nn=5; Select[Range[nn!], MemberQ[Array[Factorial, nn], Length[Divisors[#]]]&]

Crossrefs

A000005 counts divisors.

A048656 counts squarefree divisors of n!.

A325617 counts permutations of the multiset of prime factors of n!.

A336414 counts divisors of n! with distinct prime exponents.

Cf. A000142, A001221, A001222, A002982, A007489, A022559, A027423, A032741, A054991, A090630, A108731, A181796, A251753, A336416.

Sequence in context: A316793 A119251 A182358 * A212166 A293511 A336615

Adjacent sequences: A336415 A336416 A336417 * A336419 A336420 A336421

Keyword

nonn

Author

Gus Wiseman, Jul 27 2020

Status

approved