A328242 - OEIS

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

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OFFSET

1,2

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

PROG

(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));