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

Author

Gus Wiseman, Jul 27 2020

Keywords

• nonn

Comments

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

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.

Programs

Mathematica

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