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 A345893 a(n) = Sum_{d|n} n^phi(d). 1
 1, 4, 12, 24, 630, 84, 117656, 4176, 531531, 20020, 25937424612, 21192, 23298085122494, 15059100, 2562941490, 4295033120, 48661191875666868498, 68025132, 104127350297911241532860, 25600320440, 7355827597153224, 53119845582892, 907846434775996175406740561352 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..23. FORMULA a(prime(n)) = A104129(n). - Michel Marcus, Jun 29 2021 EXAMPLE a(6) = Sum_{d|6} 6^phi(d) = 6^phi(1) + 6^phi(2) + 6^phi(3) + 6^phi(6) = 6^1 + 6^1 + 6^2 + 6^2 = 84. MATHEMATICA a[n_] := DivisorSum[n, n^EulerPhi[#] &]; Array[a, 23] (* Amiram Eldar, Jun 29 2021 *) PROG (PARI) a(n) = sumdiv(n, d, n^eulerphi(d)); \\ Michel Marcus, Jun 29 2021 CROSSREFS Cf. A000010 (phi), A104129. Sequence in context: A140813 A073841 A032339 * A103471 A114979 A301042 Adjacent sequences: A345890 A345891 A345892 * A345894 A345895 A345896 KEYWORD nonn AUTHOR Wesley Ivan Hurt, Jun 28 2021 STATUS approved

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Last modified August 13 20:30 EDT 2024. Contains 375144 sequences. (Running on oeis4.)