A156190 Number of divisors d of n! such that d-1 is prime.

0, 0, 2, 6, 9, 18, 29, 43, 66, 101, 187, 257, 470, 717, 1033, 1293, 2442, 3168, 6011, 7911, 11179, 16888, 32603, 39587, 53063, 79742, 97707, 127679, 246428, 302205, 585129, 670409, 923535, 1385145, 1813935, 2099557, 4091926, 6142573, 8416157

Offset: 1

Author

Ray Chandler, Feb 05 2009

Keywords

• nonn

Links

• Ray Chandler, Table of n, a(n) for n=1..42

Crossrefs

Cf. A072627, A067847.

Programs

Mathematica

Table[Count[Divisors[n!],?(PrimeQ[#-1]&)],{n,40}] (* _Harvey P. Dale, Feb 22 2020 *)

Formula

a(n) = A072627(A000142(n)).