cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A200768 Sum of the n-th powers of the distinct prime divisors of n.

Original entry on oeis.org

0, 4, 27, 16, 3125, 793, 823543, 256, 19683, 9766649, 285311670611, 535537, 302875106592253, 678223089233, 30531927032, 65536, 827240261886336764177, 387682633, 1978419655660313589123979, 95367432689201, 558545874543637210, 81402749386839765307625
Offset: 1

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Author

Michel Lagneau, Nov 22 2011

Keywords

Examples

			a(6) = 793 because the distinct prime divisors of 6 are 2 and 3, and 2^6 + 3^6 = 793.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local p;
       add(p^n, p = numtheory:-factorset(n))
    end proc:
    map(f, [$1..30]); # Robert Israel, Feb 20 2024
  • Mathematica
    Prepend[Array[Plus@@First[Transpose[FactorInteger[#]^#]]&,100,2],0]
    Join[{0},Table[Total[FactorInteger[n][[All,1]]^n],{n,2,25}]] (* Harvey P. Dale, Jan 23 2021 *)

Formula

a(n) = Sum_{p|n} p^n. - Wesley Ivan Hurt, Jun 14 2021