A377678 a(n) = phi(n^n - n) where phi is the Euler totient function.

1, 8, 72, 768, 12400, 217728, 7112448, 94371840, 2594586816, 69139840000, 2584376931840, 58779453358080, 4367959006806720, 100089965305451520, 3251736576000000000, 200445251536048619520, 12343971160877345120064, 422076038504126628593664

Offset

2,2

Links

Amiram Eldar, Table of n, a(n) for n = 2..115

Formula

a(n) = A000010(A061190(n)).

Mathematica

a[n_] := EulerPhi[n^n - n]; Array[a, 20, 2] (* Amiram Eldar, Nov 04 2024 *)

Prog

(PARI) a(n) = eulerphi(n^n-n);

Crossrefs

Cf. A000010, A061190, A366821, A372229, A372599, A377674, A377675, A377676, A377677.

Sequence in context: A378156 A049388 A014479 * A013992 A279156 A129103

Adjacent sequences: A377675 A377676 A377677 * A377679 A377680 A377681

Keyword

nonn

Author

Sean A. Irvine, Nov 03 2024

Status

approved