A286479 a(n) = A046523(n+A000005(n)).

2, 4, 2, 2, 2, 6, 4, 12, 12, 6, 2, 12, 6, 12, 2, 6, 2, 24, 6, 6, 4, 6, 4, 32, 12, 30, 2, 6, 2, 6, 6, 6, 2, 6, 6, 12, 6, 30, 2, 48, 2, 12, 12, 12, 6, 12, 4, 6, 12, 24, 6, 6, 6, 6, 2, 64, 2, 6, 2, 72, 12, 30, 6, 2, 6, 6, 6, 6, 2, 30, 2, 60, 12, 30, 16, 6, 16, 6, 16, 60, 6, 6, 6, 96, 2, 60, 6, 96, 6, 30, 6, 12, 2, 12, 12, 72, 12, 24, 30, 2, 2, 30, 30, 48, 2, 30

Offset: 1

Author

Antti Karttunen, May 21 2017

Keywords

• nonn

Links

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

Crossrefs

Cf. A000005, A046523, A062249, A286480, A286529.

Programs

Mathematica

Table[Times @@ MapIndexed[Prime[First[#2]]^#1 &, Sort[FactorInteger[n + DivisorSigma[0, n]][[All, -1]], Greater]], {n, 106}] (* Michael De Vlieger, May 21 2017 *)

PARI

A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
A286479(n) = A046523(n+numdiv(n));
for(n=1,10000,write("b286479.txt", n, " ", A286479(n)));

Python

from sympy import factorint, divisor_count
def P(n):
    f = factorint(n)
    return sorted([f[i] for i in f])
def a046523(n):
    x=1
    while True:
        if P(n) == P(x): return x
        else: x+=1
def a(n): return a046523(n + divisor_count(n)) # Indranil Ghosh, May 21 2017

Scheme

(define (A286479 n) (A046523 (+ n (A000005 n))))

Formula

a(n) = A046523(A062249(n)) = A046523(n+A000005(n)).