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URL: https://oeis.org/A388264

⇱ A388264 - OEIS


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A388264
a(n) = gcd(A276086(n), A276086(sigma(n)-n)), where A276086 is the primorial base exp-function, and sigma is the sum of divisors function.
3
1, 1, 2, 3, 2, 5, 2, 5, 3, 15, 2, 25, 2, 15, 30, 75, 2, 125, 2, 375, 30, 75, 2, 5, 5, 75, 50, 5625, 2, 7, 2, 7, 6, 3, 2, 35, 2, 15, 30, 105, 2, 175, 2, 105, 42, 75, 2, 175, 5, 175, 750, 1575, 2, 35, 50, 21, 750, 21, 2, 49, 2, 21, 42, 147, 2, 245, 2, 105, 30, 735, 2, 49, 2, 105, 350, 441, 50, 49, 2, 3675, 105, 525
OFFSET
1,3
FORMULA
a(n) = gcd(A276086(n), A276086(A001065(n))) = gcd(A276086(n), A379493(n)).
PROG
(PARI)
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A388264(n) = gcd(A276086(n), A276086(sigma(n)-n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 16 2025
STATUS
approved