A295502 a(n) = phi(5^n-1), where phi is Euler's totient function (A000010).

2, 8, 60, 192, 1400, 4320, 39060, 119808, 894240, 2912000, 24414060, 62208000, 610351560, 1959874560, 13154400000, 44043337728, 380537036928, 997843069440, 9485297382000, 25606963200000, 230106651919200, 748687423334400, 5959800062798400, 15138938880000000

Offset

1,1

Links

Max Alekseyev, Table of n, a(n) for n = 1..502

Eric W. Weisstein, MathWorld: Totient Function

Wikipedia, Euler's totient function

Formula

a(n) = n*A027741(n).

Prog

(PARI) {a(n) = eulerphi(5^n-1)}

Crossrefs

phi(k^n-1): A053287 (k=2), A295500 (k=3), A295501 (k=4), this sequence (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: A203208 A181010 A197941 * A196076 A027278 A001415

Adjacent sequences: A295499 A295500 A295501 * A295503 A295504 A295505

Keyword

nonn

Author

Seiichi Manyama, Nov 22 2017

Status

approved