|
%I #15 Jan 09 2024 18:46:37
%S 6,36,432,1728,27000,139968,1778112,6635520,113467392,534600000,
%T 6963536448,26121388032,465193834560,2427720325632,28548223200000,
%U 109586090557440,1910296842179040,9618417501143040,123523151337020736,406467072000000000,7713001620195508224
%N a(n) = phi(8^n-1), where phi is Euler's totient function (A000010).
%H Max Alekseyev, <a href="/A366654/b366654.txt">Table of n, a(n) for n = 1..500</a>
%F a(n) = A053287(3*n). - _Max Alekseyev_, Jan 09 2024
%t EulerPhi[8^Range[30] - 1]
%o (PARI) {a(n) = eulerphi(8^n-1)}
%o (Python)
%o from sympy import totient
%o def A366654(n): return totient((1<<3*n)-1) # _Chai Wah Wu_, Oct 15 2023
%Y 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).
%Y Cf. A000010, A010705, A024088, A057953, A059890, A274908, A366651, A366652, A366653.
%K nonn
%O 1,1
%A _Sean A. Irvine_, Oct 15 2023
|
