A366760 a(n) = phi(n!+1), where phi is Euler's totient function (A000010).

1, 1, 2, 6, 20, 110, 612, 4970, 39600, 337680, 3298900, 39916800, 442155168, 6151996372, 83387930692, 1282826630160, 19089488332800, 355148307803520, 5427568925856000, 119931789135468100, 2432901890279317572, 49902667163053013232, 1073067539495604750240

Offset: 0

Author

Sean A. Irvine, Oct 20 2023

Keywords

• nonn

Crossrefs

Cf. A038507, A000010, A048855, A366759.

Programs

Mathematica

EulerPhi[Range[0,25]!+1] (* Paolo Xausa, Oct 21 2023 *)

PARI

{a(n) = eulerphi(n!+1)}

Python

from math import factorial
from sympy import totient
def A366760(n): return totient(factorial(n)+1) # Chai Wah Wu, Oct 20 2023

Formula

a(n) = A000010(A038507(n)).