login
A342394
a(n) = Sum_{k=1..n} k^(gcd(k,n) - 1).
3
1, 3, 11, 68, 629, 7793, 117655, 2097228, 43046772, 1000000649, 25937424611, 743008379146, 23298085122493, 793714773371841, 29192926025401528, 1152921504608945960, 48661191875666868497, 2185911559738739835591, 104127350297911241532859
OFFSET
1,2
FORMULA
If p is prime, a(p) = p-1 + p^(p-1) = A173235(p) = A056665(p).
MATHEMATICA
a[n_] := Sum[k^(GCD[k, n] - 1), {k, 1, n}]; Array[a, 19] (* Amiram Eldar, Mar 10 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, k^(gcd(k, n)-1));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Mar 10 2021
STATUS
approved