A056820 Euler totient function of Cullen numbers (A002064), n*2^n +1.

1, 2, 6, 20, 48, 132, 240, 528, 1364, 4180, 7560, 20784, 42768, 70992, 151632, 446208, 986880, 1688400, 4006800, 6080256, 13843440, 42125380, 79567488, 152712000, 292573440, 526051328, 797636448, 2942476992, 7257012896

Offset: 0

Author

Robert G. Wilson v, Aug 31 2000

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 0..848

Crossrefs

Cf. A000010, A002064.

Programs

Mathematica

Table[ EulerPhi[ n*2^n + 1 ], {n, 1, 30} ]

Formula

a(n) = A000010(A002064(n)). - Amiram Eldar, Nov 29 2019