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A324646
a(n) = gcd(n, A276086(n-1)).
4
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
1,2
FORMULA
a(n) = gcd(n, A276086(n-1)).
a(A002110(n)) = A002110(n) for all n >= 0.
PROG
(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));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Mar 11 2019
STATUS
approved