A285708 a(n) = n / A285707(n).

1, 2, 3, 2, 5, 3, 7, 2, 3, 5, 11, 4, 13, 7, 5, 2, 17, 9, 19, 5, 7, 11, 23, 4, 5, 13, 3, 7, 29, 10, 31, 2, 11, 17, 7, 9, 37, 19, 13, 5, 41, 7, 43, 11, 5, 23, 47, 4, 7, 5, 17, 13, 53, 9, 11, 8, 19, 29, 59, 10, 61, 31, 9, 2, 13, 33, 67, 17, 23, 35, 71, 9, 73, 37, 5, 19, 11, 13, 79, 5, 3, 41, 83, 28, 17, 43, 29, 11, 89, 10, 13, 23, 31, 47, 19, 32, 97, 49, 11, 5

Offset

1,2

Links

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

Formula

a(n) = n / A285707(n).

For n > 1, a(n) = n / gcd(n, A079277(n)).

Prog

(Scheme) (define (A285708 n) (/ n (A285707 n)))
(Python)
from sympy import divisors, gcd
from sympy.ntheory.factor_ import core
def a007947(n): return max(i for i in divisors(n) if core(i) == i)
def a079277(n):
    k=n - 1
    while True:
        if a007947(k*n) == a007947(n): return k
        else: k-=1
def a285707(n): return 1 if n==1 else gcd(n, a079277(n))
print([n//a285707(n) for n in range(1, 151)]) # Indranil Ghosh, Apr 27 2017

Crossrefs

Cf. A079277, A285707.

Sequence in context: A109395 A145254 A163457 * A072593 A348907 A039635

Adjacent sequences: A285705 A285706 A285707 * A285709 A285710 A285711

Keyword

nonn

Author

Antti Karttunen, Apr 26 2017

Status

approved