A227032 Numbers k such that the sum of the first k prime powers > 1 is divisible by k.

1, 3, 36, 75, 96, 692, 732, 798, 2407, 3102, 3941, 4003, 101423, 131281, 337708, 399418, 460530, 480328, 594577, 26121722, 287922744, 702590009, 870360308, 18056232172, 35392830431, 73730356109, 169558413390, 268671255173

Offset

1,2

Links

Table of n, a(n) for n=1..28.

Example

The first 3 prime powers > 1 are 2, 3, 2^2 and 2+3+2^2 is divisible by 3, so 3 is a term.

Mathematica

seq = {}; s = n = 0; p = 1; While[n < 10^4, If[Length@FactorInteger[++p] == 1 && Mod[s += p, ++n] == 0, AppendTo[seq, n]]]; seq

Crossrefs

Cf. A225792.

Sequence in context: A113799 A072682 A158207 * A153448 A325838 A140958

Adjacent sequences: A227029 A227030 A227031 * A227033 A227034 A227035

Keyword

nonn

Author

Giovanni Resta, Jun 28 2013

Status

approved