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A366579
a(n) = phi(3^n+1), where phi is Euler's totient function (A000010).
12
1, 2, 4, 12, 40, 120, 288, 1092, 3072, 7776, 23600, 87120, 259200, 797160, 1847104, 5832000, 21523360, 63672480, 152845056, 580921200, 1700870400, 4368821184, 12550120000, 47071589412, 130459631616, 413939700000, 997562438080, 3012122557440, 11159367815680
OFFSET
0,2
LINKS
FORMULA
a(n) = phi(3^n+1) = A000010(A034472(n)).
MATHEMATICA
EulerPhi[3^Range[0, 30]+1] (* Paolo Xausa, Oct 15 2023 *)
PROG
(PARI) {a(n) = eulerphi(3^n+1)}
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 13 2023
STATUS
approved