A336644 a(n) = (n-rad(n)) / core(n), where rad(n) and core(n) give the squarefree kernel and squarefree part of n, respectively.

0, 0, 0, 2, 0, 0, 0, 3, 6, 0, 0, 2, 0, 0, 0, 14, 0, 6, 0, 2, 0, 0, 0, 3, 20, 0, 8, 2, 0, 0, 0, 15, 0, 0, 0, 30, 0, 0, 0, 3, 0, 0, 0, 2, 6, 0, 0, 14, 42, 20, 0, 2, 0, 8, 0, 3, 0, 0, 0, 2, 0, 0, 6, 62, 0, 0, 0, 2, 0, 0, 0, 33, 0, 0, 20, 2, 0, 0, 0, 14, 78, 0, 0, 2, 0, 0, 0, 3, 0, 6, 0, 2, 0, 0, 0, 15, 0, 42, 6, 90, 0, 0, 0, 3, 0

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Formula

a(n) = A066503(n) / A007913(n) = (n-A007947(n)) / A007913(n).

a(n) = A008833(n) - A336643(n).

Prog

(PARI) A336644(n) = ((n-factorback(factorint(n)[, 1])) / core(n));
(Python)
from math import prod
from sympy.ntheory.factor_ import primefactors, core
def A336644(n): return (n-prod(primefactors(n)))//core(n) # Chai Wah Wu, Dec 30 2021

Crossrefs

Cf. A007913, A007947, A008833, A066503, A336642, A336643.

Sequence in context: A076260 A245527 A287871 * A135416 A134309 A051516

Adjacent sequences: A336641 A336642 A336643 * A336645 A336646 A336647

Keyword

nonn

Author

Antti Karttunen, Jul 28 2020

Status

approved