A284253 a(n) = n / A284252(n).

1, 2, 3, 4, 5, 6, 7, 8, 9, 2, 11, 12, 13, 2, 15, 16, 17, 18, 19, 4, 21, 2, 23, 24, 25, 2, 27, 4, 29, 6, 31, 32, 3, 2, 35, 36, 37, 2, 3, 8, 41, 6, 43, 4, 45, 2, 47, 48, 49, 10, 3, 4, 53, 54, 55, 8, 3, 2, 59, 12, 61, 2, 63, 64, 65, 6, 67, 4, 3, 14, 71, 72, 73, 2, 75, 4, 77, 6, 79, 16, 81, 2, 83, 12, 85, 2, 3, 8, 89, 18, 91, 4, 3, 2, 95, 96, 97, 14, 9, 20, 101, 6

Offset: 1

Author

Antti Karttunen, Mar 24 2017

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A020639, A284252, A284254, A284255, A284256, A284257, A284258, A284259.

Programs

Mathematica

a[n_] := Block[{p = First /@ FactorInteger[n]}, n / SelectFirst[p, # > p[[1]]^2 &, 1]]; Array[a, 120] (* Giovanni Resta, Mar 24 2017 *)

PARI

a(n) = if(n<2, return(1), my(f=factor(n)[, 1]); for(i=2, #f, if(f[i]>f[1]^2, return(f[i]))); return(1));
for(n=1, 151, print1(n/a(n),", ")) \\ Indranil Ghosh, after David A. Corneth, Mar 24 2017

Python

from sympy import primefactors
def a(n):
    pf = primefactors(n)
    if pf: min_pf2 = min(pf)**2
    for i in pf:
        if i > min_pf2: return i
    return 1
print([n//a(n) for n in range(1, 151)]) # Indranil Ghosh, Mar 24 2017

Scheme

(define (A284253 n) (/ n (A284252 n)))

Formula

a(n) = n / A284252(n).