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A326047
a(n) = gcd(n-A050449(n), n-A050452(n)), where A050449 and A050452 give the sum of divisors of the form 4k+1 and of the form 4k+3, respectively.
17
1, 1, 2, 1, 1, 1, 6, 1, 1, 2, 10, 1, 1, 1, 3, 1, 1, 1, 18, 2, 1, 1, 22, 1, 1, 2, 1, 3, 1, 12, 30, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 4, 42, 1, 3, 1, 46, 1, 1, 1, 3, 2, 1, 4, 1, 1, 1, 2, 58, 6, 1, 1, 2, 1, 1, 4, 66, 2, 1, 4, 70, 1, 1, 2, 2, 3, 1, 4, 78, 2, 1, 2, 82, 2, 1, 1, 3, 1, 1, 6, 7, 1, 1, 1, 1, 1, 1, 1, 14, 1, 1, 12, 102, 2, 9
OFFSET
1,3
LINKS
FORMULA
a(n) = gcd(A326049(n), A326052(n)) = gcd(n-A050449(n), n-A050452(n)).
a(2n-1) = A326048(2n-1) for all n.
PROG
(PARI)
A050449(n) = sumdiv(n, d, d*((d % 4) == 1)); \\ From A050449
A326049(n) = (n-A050449(n));
A050452(n) = sumdiv(n, d, d*(3==(d % 4)));
A326052(n) = (n-A050452(n));
A326047(n) = gcd(A326049(n), A326052(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 04 2019
STATUS
approved