A255429 - OEIS

A255429

Numbers with a prime number of nontrivial divisors.

6, 8, 10, 14, 15, 16, 21, 22, 26, 27, 33, 34, 35, 36, 38, 39, 46, 51, 55, 57, 58, 62, 64, 65, 69, 74, 77, 81, 82, 85, 86, 87, 91, 93, 94, 95, 100, 106, 111, 115, 118, 119, 122, 123, 125, 129, 133, 134, 141, 142, 143, 144, 145, 146, 155, 158, 159, 161, 166, 177, 178, 183, 185, 187, 194, 196

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OFFSET

1,1

COMMENTS

Empirically, numbers in this sequence seem to have few divisors.

This sequence appears to be the union of A130763 and the squares of A225649. - Kellen Myers, Apr 21 2015

LINKS

Table of n, a(n) for n=1..66.

FORMULA

{n: A070824(n) in A000040}.

MATHEMATICA

seq[n_] := Select[Range[n], PrimeQ[DivisorSigma[0, #] - 2] &] (* Kellen Myers, Apr 21 2015 *)