A324646 a(n) = gcd(n, A276086(n-1)).

1, 2, 3, 2, 1, 6, 1, 2, 3, 10, 1, 6, 1, 2, 15, 2, 1, 18, 1, 10, 3, 2, 1, 6, 25, 2, 3, 2, 1, 30, 1, 2, 3, 2, 7, 18, 1, 2, 3, 10, 1, 42, 1, 2, 15, 2, 1, 6, 7, 50, 3, 2, 1, 18, 5, 14, 3, 2, 1, 30, 1, 2, 21, 2, 1, 6, 1, 2, 3, 70, 1, 18, 1, 2, 75, 2, 7, 6, 1, 10, 3, 2, 1, 42, 5, 2, 3, 2, 1, 90, 7, 2, 3, 2, 1, 6, 1, 98, 3, 10, 1, 6, 1, 2, 105

Offset: 1

Author

Antti Karttunen, Mar 11 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..30030
• Index entries for sequences related to primorial base
• Index entries for sequences related to primorial numbers

Crossrefs

Cf. A002110, A276086, A324198, 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; };
A324646(n) = gcd(n,A276086(n-1));

Formula

a(n) = gcd(n, A276086(n-1)).

a(A002110(n)) = A002110(n) for all n >= 0.