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A326140
a(n) = gcd(A318878(n), A318879(n)).
9
1, 1, 2, 1, 4, 2, 6, 1, 5, 2, 10, 2, 12, 2, 6, 1, 16, 1, 18, 2, 10, 2, 22, 2, 19, 2, 14, 6, 28, 6, 30, 1, 18, 2, 22, 1, 36, 2, 22, 2, 40, 2, 42, 2, 12, 2, 46, 2, 41, 1, 30, 6, 52, 2, 38, 2, 34, 2, 58, 6, 60, 2, 22, 1, 46, 6, 66, 2, 42, 2, 70, 1, 72, 2, 26, 6, 58, 2, 78, 2, 41, 2, 82, 2, 62, 2, 54, 2, 88, 6, 70, 2, 58, 2
OFFSET
1,3
LINKS
PROG
(PARI) A326140(n) = { my(t=0, u=0); fordiv(n, d, d -= 2*eulerphi(d); if(d<0, t -= d, u += d)); gcd(t, u); };
(PARI)
A318878(n) = sumdiv(n, d, d=(2*eulerphi(d))-d; (d>0)*d);
A318879(n) = sumdiv(n, d, d=d-(2*eulerphi(d)); (d>0)*d);
A326140(n) = gcd(A318878(n), A318879(n));
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 09 2019
STATUS
approved