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A342370
a(n) = Sum_{k=1..n} gcd(k,n)^(k-1).
3
1, 3, 11, 68, 629, 7797, 117655, 2097254, 43046979, 1000000799, 25937424611, 743008402000, 23298085122493, 793714773374529, 29192926027528343, 1152921504613147242, 48661191875666868497, 2185911559739107208115, 104127350297911241532859, 5242880000000008181608132
OFFSET
1,2
LINKS
FORMULA
If p is prime, a(p) = p-1 + p^(p-1) = A173235(p).
MATHEMATICA
a[n_] := Sum[GCD[k, n]^(k - 1), {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Mar 13 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, gcd(k, n)^(k-1));
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 13 2021
EXTENSIONS
a(19) and beyond from Martin Ehrenstein, Mar 13 2021
STATUS
approved