login
A366654
a(n) = phi(8^n-1), where phi is Euler's totient function (A000010).
14
6, 36, 432, 1728, 27000, 139968, 1778112, 6635520, 113467392, 534600000, 6963536448, 26121388032, 465193834560, 2427720325632, 28548223200000, 109586090557440, 1910296842179040, 9618417501143040, 123523151337020736, 406467072000000000, 7713001620195508224
OFFSET
1,1
LINKS
FORMULA
a(n) = A053287(3*n). - Max Alekseyev, Jan 09 2024
MATHEMATICA
EulerPhi[8^Range[30] - 1]
PROG
(PARI) {a(n) = eulerphi(8^n-1)}
(Python)
from sympy import totient
def A366654(n): return totient((1<<3*n)-1) # Chai Wah Wu, Oct 15 2023
CROSSREFS
phi(k^n-1): A053287 (k=2), A295500 (k=3), A295501 (k=4), A295502 (k=5), A366623 (k=6), A366635 (k=7), this sequence (k=8), A366663 (k=9), A295503 (k=10), A366685 (k=11), A366711 (k=12).
Sequence in context: A185085 A201540 A195229 * A367488 A339300 A296389
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 15 2023
STATUS
approved