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%I #12 Mar 10 2021 12:28:50
%S 1,3,12,90,1305,15713,376768,6163324,176787369,3769360335,
%T 142364319636,3152514811878,154718778284161,4340009168261557,
%U 210971169749009040,7281661102087491416,435659030617933827153,14181101408651996188995
%N a(n) = Sum_{k=1..n} k^(n/gcd(k,n)).
%F If p is prime, a(p) = A121706(p) + p.
%t a[n_] := Sum[k^(n/GCD[k, n]), {k, 1, n}]; Array[a, 18] (* _Amiram Eldar_, Mar 10 2021 *)
%o (PARI) a(n) = sum(k=1, n, k^(n/gcd(k, n)));
%Y Cf. A121706, A332620, A342389, A342396.
%K nonn,easy
%O 1,2
%A _Seiichi Manyama_, Mar 10 2021
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