A104354 Euler's totient of A104350(n).

1, 1, 2, 4, 16, 48, 288, 576, 1728, 8640, 86400, 259200, 3110400, 21772800, 108864000, 217728000, 3483648000, 10450944000, 188116992000, 940584960000, 6584094720000, 72425041920000, 1593350922240000, 4780052766720000, 23900263833600000, 310703429836800000

Offset: 1

Author

Reinhard Zumkeller, Mar 06 2005

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..640
• Reinhard Zumkeller, Products of largest prime factors of numbers <= n.

Crossrefs

Cf. A000010, A048855, A104350.

Programs

Mathematica

EulerPhi[FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 30]]] (* Amiram Eldar, Apr 08 2024 *)

PARI

gpf(n) = my(f=factor(n)[, 1]); f[#f];
a(n) = eulerphi(prod(i=2, n, gpf(i))); \\ Michel Marcus, Nov 12 2023

Formula

a(n) = A000010(A104350(n)).

Extensions

a(1) prepended by Michel Marcus, Nov 12 2023