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

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.

Cf. A328252 (nonsquarefree terms), A157037, A192192, A327978 (other subsequences).

Sequence in context: A001948 A121912 A325113 * A189529 A120514 A101886

Adjacent sequences: A328390 A328391 A328392 * A328394 A328395 A328396

Keyword

nonn

Author

Antti Karttunen, Oct 19 2019

Status

approved