A328242 Numbers k such that A003415(A276086(k)) is a squarefree number, where A003415 is the arithmetic derivative, and A276086 is the primorial base exp-function.

1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 14, 15, 17, 30, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 46, 47, 60, 61, 62, 63, 65, 66, 67, 68, 69, 71, 73, 74, 75, 76, 77, 210, 211, 212, 213, 215, 217, 218, 219, 220, 221, 223, 225, 226, 227, 241, 242, 243, 245, 246, 247, 248, 249, 250, 251, 254, 255, 256, 257, 270, 273, 274, 275, 276, 277

Offset: 1

Author

Antti Karttunen, Oct 10 2019

Keywords

• nonn

Comments

Numbers n such that A276086(n) is either in A328234 or in A000040 (i.e., it is a prime, in which case n itself is a primorial, A002110).

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10681
• Index entries for sequences related to primorial base

Crossrefs

Positions of 1's in A370130. Subsequence of A370132.

Cf. A000040, A002110, A003415, A005117, A008966, A276086, A327860, A328234.

Cf. A328241 (complement).

Cf. A328233, A328240 (subsequences).

Programs

PARI

A327860(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= (p^e); s += (e/p); n = n\p; p = nextprime(1+p)); (s*m); };
isA328242(n) = issquarefree(A327860(n));