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

1,3

Links

Amiram Eldar, Table of n, a(n) for n = 1..640

Reinhard Zumkeller, Products of largest prime factors of numbers <= n.

Formula

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

Mathematica

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

Prog

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

Crossrefs

Cf. A000010, A048855, A104350.

Sequence in context: A248748 A350646 A165905 * A153948 A284730 A255730

Adjacent sequences: A104351 A104352 A104353 * A104355 A104356 A104357

Keyword

nonn

Author

Reinhard Zumkeller, Mar 06 2005

Extensions

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

Status

approved