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A181540
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a(n) = Sum_{k=0..n} gcd(n,k)*phi(k).
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2
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0, 1, 3, 8, 13, 26, 29, 54, 59, 84, 93, 142, 139, 202, 195, 244, 259, 352, 327, 444, 433, 508, 505, 656, 639, 776, 719, 866, 889, 1054, 1057, 1208, 1151, 1332, 1255, 1624, 1575, 1728, 1579, 1886, 2011, 2130, 2159, 2348, 2329, 2716, 2329
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OFFSET
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0,3
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COMMENTS
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LINKS
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MAPLE
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A181540 := n -> add(igcd(n, k)*numtheory[phi](k), k=0..n);
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MATHEMATICA
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Table[Sum[GCD[n, k]EulerPhi[k], {k, 0, n}], {n, 0, 50}] (* Harvey P. Dale, Jul 12 2020 *)
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PROG
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(PARI) a(n) = sum(k=1, n, gcd(n, k)*eulerphi(k)); \\ Michel Marcus, May 18 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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