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A373361
a(n) = gcd(n, A276085(n)), where A276085 is the primorial base log-function.
4
1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 3, 4, 1, 3, 1, 1, 1, 1, 1, 6, 1, 19, 1, 1, 1, 3, 1, 4, 5, 1, 1, 6, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 10, 1, 1, 1, 2, 1, 3, 1, 4, 1, 1, 1, 1, 1, 1, 1, 4, 1, 3, 1, 10, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 13, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1
OFFSET
1,4
PROG
(PARI)
A002110(n) = prod(i=1, n, prime(i));
A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*A002110(primepi(f[k, 1])-1)); };
A373361(n) = gcd(n, A276085(n));
CROSSREFS
Cf. A108269 (positions of even terms), A328981 (their characteristic function), A359794 (positions of odd terms), A359832 (their characteristic function, parity of terms).
Cf. also A324198, A373145, A373362.
Sequence in context: A111957 A125168 A324725 * A328392 A051794 A333305
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 02 2024
STATUS
approved