A056821 Totient of the Woodall numbers (A003261), n*2^n -1.

1, 6, 22, 36, 104, 382, 712, 1936, 4320, 6824, 15012, 46992, 79344, 183000, 421008, 480000, 1453784, 4658784, 8877792, 20958480, 38887680, 61284600, 110250264, 388201176, 719023536, 1734432480, 2889658368, 4745378304, 10350643968, 32212254718, 66251144568

Offset: 1

Author

Robert G. Wilson v, Aug 31 2000

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..853 (terms 1..150 from Vincenzo Librandi)

Crossrefs

Cf. A000010, A003261.

Programs

Magma

[EulerPhi(n*2^n-1): n in [1..30]]; // Vincenzo Librandi, Apr 15 2019

Maple

a:= n-> numtheory[phi](n*2^n-1):
seq(a(n), n=1..35);  # Alois P. Heinz, Apr 15 2019

Mathematica

Table[EulerPhi[n 2^n - 1], {n, 1, 35}]

PARI

a(n) = eulerphi(n*2^n -1); \\ Michel Marcus, Apr 15 2019

Formula

a(n) = A000010(A003261(n)).