A328393 - OEIS

A328393

Numbers whose arithmetic derivative (A003415) is a squarefree number (A005117).

2, 3, 5, 6, 7, 9, 10, 11, 13, 17, 18, 19, 21, 22, 23, 25, 26, 29, 30, 31, 33, 34, 37, 38, 41, 42, 43, 45, 47, 49, 53, 57, 58, 59, 61, 62, 63, 66, 67, 69, 70, 71, 73, 74, 75, 78, 79, 82, 83, 85, 89, 90, 93, 97, 98, 101, 102, 103, 105, 106, 107, 109, 110, 113, 114, 117, 118, 121, 126, 127, 129, 130, 131, 133, 134, 137, 139, 142

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

PROG

(PARI)

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));

isA328393(n) = issquarefree(A003415(n));

CROSSREFS

Union of A000040 and A328234. Complement of A328303.

Cf. A005117, A008966, A003415.