A366821 a(n) is phi(n^n-1) where phi is the Euler totient function.
2, 12, 128, 1400, 30240, 264992, 6635520, 141087744, 5890320000, 114117380608, 4662793175040, 99053063903040, 5470524984113280, 167080949856000000, 9208981628670443520, 413582117375670921216, 29531731481729468006400, 659473218553437863041320
Offset: 2
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 2..138 (terms 2..102 from Robert G. Wilson v)
Programs
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Maple
a:= n-> numtheory[phi](n^n-1): seq(a(n), n=2..20); # Alois P. Heinz, Oct 26 2023
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Mathematica
Array[EulerPhi[#^# - 1] &, 18, 2] (* Michael De Vlieger, Oct 24 2023 *)
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PARI
a(n) = eulerphi(n^n-1);