A324645 a(n) = gcd(d(n), A276086(n)), where d(n) gives the number of divisors (A000005).

1, 1, 2, 3, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 2, 5, 2, 1, 2, 3, 2, 1, 2, 1, 1, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 6, 1, 2, 5, 1, 3, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 6, 7, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 6, 3, 2, 1, 2, 5, 5, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 6, 9, 2, 1, 2, 1, 2

Offset: 1

Author

Antti Karttunen, Mar 11 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..30030

Crossrefs

Cf. A000005, A009191, A276086, A324644.

Programs

PARI

A276086(n) = { my(i=0,m=1,pr=1,nextpr); while((n>0),i=i+1; nextpr = prime(i)*pr; if((n%nextpr),m*=(prime(i)^((n%nextpr)/pr));n-=(n%nextpr));pr=nextpr); m; };
A324645(n) = gcd(numdiv(n),A276086(n));

Formula

a(n) = gcd(A000005(n), A276086(n)).