A295500 a(n) = phi(3^n-1), where phi is Euler's totient function (A000010).

1, 4, 12, 32, 110, 288, 1092, 2560, 9072, 26400, 84700, 165888, 797160, 2384928, 6019200, 15728640, 64533700, 141087744, 580765248, 1246080000, 4823425152, 14758128000, 46070066188, 85996339200, 385087175000, 1270928131200, 3474144608256, 8810420097024

Offset

1,2

Links

Max Alekseyev, Table of n, a(n) for n = 1..690

Eric Weisstein's World of Mathematics, Totient Function

Wikipedia, Euler's totient function

Formula

a(n) = n*A027385(n).

a(n) = A000010(A024023(n)). - Michel Marcus, Jun 18 2024

Mathematica

EulerPhi[3^Range[30] - 1] (* Paolo Xausa, Jun 18 2024 *)

Prog

(PARI) {a(n) = eulerphi(3^n-1)}

Crossrefs

Cf. A000010, A024023, A027385.

phi(k^n-1): A053287 (k=2), this sequence (k=3), A295501 (k=4), A295502 (k=5), A366623 (k=6), A366635 (k=7), A366654 (k=8), A366663 (k=9), A295503 (k=10), A366685 (k=11), A366711 (k=12).

Sequence in context: A001665 A066536 A265212 * A168078 A225894 A318637

Adjacent sequences: A295497 A295498 A295499 * A295501 A295502 A295503

Keyword

nonn

Author

Seiichi Manyama, Nov 22 2017

Status

approved