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 A373458 Expansion of Sum_{p prime} x^p/(1 - p*x^p). 2
 0, 1, 1, 2, 1, 7, 1, 8, 9, 21, 1, 59, 1, 71, 106, 128, 1, 499, 1, 637, 778, 1035, 1, 4235, 625, 4109, 6561, 8535, 1, 39192, 1, 32768, 59170, 65553, 18026, 308219, 1, 262163, 531610, 602413, 1, 2659706, 1, 2098483, 5173594, 4194327, 1, 22737515, 117649, 18730341 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Table of n, a(n) for n=1..50. FORMULA a(n) = Sum_{p|n prime} p^(n/p - 1). If p is prime, a(p) = 1. MAPLE A373458 := proc(n) local a, d ; a := 0 ; for d in numtheory[divisors](n) do if isprime(d) then a := a+d^(n/d-1) ; end if; end do: a ; end proc: seq(A373458(n), n=1..20) ; # R. J. Mathar, Jun 07 2024 PROG (PARI) a(n) = sumdiv(n, d, isprime(d)*d^(n/d-1)); CROSSREFS Cf. A001221, A305614, A373459. Sequence in context: A345301 A160417 A117044 * A280691 A092666 A019426 Adjacent sequences: A373454 A373455 A373456 * A373459 A373460 A373461 KEYWORD nonn,easy AUTHOR Seiichi Manyama, Jun 06 2024 STATUS approved

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Last modified August 9 02:18 EDT 2024. Contains 375024 sequences. (Running on oeis4.)