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A342389
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a(n) = Sum_{k=1..n} k^gcd(k,n).
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3
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1, 5, 30, 264, 3135, 46709, 823564, 16777528, 387420759, 10000003265, 285311670666, 8916100500148, 302875106592331, 11112006826381965, 437893890380965260, 18446744073726350224, 827240261886336764313, 39346408075296928032645
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OFFSET
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1,2
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LINKS
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FORMULA
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If p is prime, a(p) = A000217(p-1) + p^p = (p-1)*p/2 + p^p.
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MATHEMATICA
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a[n_] := Sum[k^GCD[k, n], {k, 1, n}]; Array[a, 18] (* Amiram Eldar, Mar 10 2021 *)
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PROG
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(PARI) a(n) = sum(k=1, n, k^gcd(k, n));
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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