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 A342539 a(n) = Sum_{k=1..n} phi(gcd(k, n))^n. 4
 1, 2, 10, 19, 1028, 132, 279942, 65798, 10078726, 2097160, 100000000010, 16797702, 106993205379084, 156728328204, 35186519703560, 281479271809036, 295147905179352825872, 203119914385420, 708235345355337676357650, 1152924803145924620, 46005163783270994804748, 20000000000000000000020 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..388 FORMULA a(n) = Sum_{d|n} phi(n/d) * phi(d)^n. If p is prime, a(p) = p-1 + (p-1)^p. a(n) = Sum_{k=1..n} phi(n/gcd(n,k))^(n-1)*phi(gcd(n,k)). - Richard L. Ollerton, May 09 2021 MATHEMATICA a[n_] := DivisorSum[n, EulerPhi[n/#] * EulerPhi[#]^n &]; Array[a, 20] (* Amiram Eldar, Mar 15 2021 *) PROG (PARI) a(n) = sum(k=1, n, eulerphi(gcd(k, n))^n); (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*eulerphi(d)^n); CROSSREFS Cf. A000010, A029935, A332517, A342487, A342534, A342535, A342540, A342541, A342543. Sequence in context: A259096 A317859 A342543 * A346810 A347024 A009342 Adjacent sequences: A342536 A342537 A342538 * A342540 A342541 A342542 KEYWORD nonn AUTHOR Seiichi Manyama, Mar 15 2021 STATUS approved

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Last modified September 23 19:57 EDT 2023. Contains 365554 sequences. (Running on oeis4.)