A366822 -id:A366822 - cp's OEIS frontend

A377674 a(n) = phi(n^n + n) where phi is the Euler totient function.

1, 2, 8, 96, 1248, 12000, 259200, 5461344, 129140160, 2725643520, 127561104000, 2743415522496, 139778722137600, 2504616361228800, 111747349423990784, 8644660582219776000, 387774574486565683200, 12306643656809728412160, 816897235219321957908480

Offset: 1

Sean A. Irvine, Nov 03 2024

nonn

Amiram Eldar, Table of n, a(n) for n = 1..116

Cf. A000010, A066068, A366822, A372228, A372546, A377671, A377672, A377673.

a[n_] := EulerPhi[n^n + n]; Array[a, 20] (* Amiram Eldar, Nov 04 2024 *)

PARI
```
a(n) = eulerphi(n^n+n);
```

a(n) = A000010(A066068(n)).

A366821 a(n) is phi(n^n-1) where phi is the Euler totient function.

Original entry on oeis.org

2, 12, 128, 1400, 30240, 264992, 6635520, 141087744, 5890320000, 114117380608, 4662793175040, 99053063903040, 5470524984113280, 167080949856000000, 9208981628670443520, 413582117375670921216, 29531731481729468006400, 659473218553437863041320

Offset: 2

Sean A. Irvine, Oct 24 2023

nonn

Amiram Eldar, Table of n, a(n) for n = 2..138 (terms 2..102 from Robert G. Wilson v)

Cf. A000010, A048861, A064447, A309941, A334167, A344870, A366819, A366822.

a:= n-> numtheory[phi](n^n-1):
seq(a(n), n=2..20);  # Alois P. Heinz, Oct 26 2023

Array[EulerPhi[#^# - 1] &, 18, 2] (* Michael De Vlieger, Oct 24 2023 *)

PARI
```
a(n) = eulerphi(n^n-1);
```

a(n) = A000010(A048861(n)).

cp's OEIS Frontend

A377674 a(n) = phi(n^n + n) where phi is the Euler totient function.

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