A079092 Euler's totient of (prime(n)+1)*(prime(n+1)+1)/4.

2, 2, 4, 8, 12, 36, 24, 32, 48, 64, 144, 216, 120, 160, 216, 216, 240, 480, 384, 432, 576, 384, 432, 1008, 1344, 768, 864, 720, 1440, 1152, 1280, 1320, 1056, 1200, 1440, 2808, 3120, 1920, 2016, 2016, 1728, 2304, 3072, 5760, 2400, 4160, 4992, 3456, 3168, 6336

Offset: 1

Author

Reinhard Zumkeller, Dec 22 2002

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000010, A079079.

Programs

Haskell

a079092 = a000010 . a079079  -- Reinhard Zumkeller, Oct 09 2012

Mathematica

a[n_] := EulerPhi[(Prime[n]+1) * (Prime[n+1]+1) / 4]; Array[a, 100] (* Amiram Eldar, Apr 06 2025 *)

PARI

a(n) = eulerphi((prime(n)+1)*(prime(n+1)+1)/4); \\ Amiram Eldar, Apr 06 2025

Formula

a(n) = A000010(A079079(n)).