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A326048
a(n) = gcd(n-A050449(n), A082052(n)-n), where A050449 and A082052 give the sum of divisors of the form 4k+1, and not of that form, respectively.
17
1, 1, 2, 1, 1, 5, 6, 1, 1, 2, 10, 1, 1, 1, 3, 1, 1, 1, 18, 2, 1, 1, 22, 1, 1, 2, 1, 27, 1, 12, 30, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 4, 42, 1, 3, 5, 46, 1, 1, 1, 3, 2, 1, 4, 1, 1, 1, 2, 58, 6, 1, 1, 2, 1, 1, 4, 66, 10, 1, 4, 70, 1, 1, 2, 2, 3, 1, 4, 78, 2, 1, 2, 82, 2, 1, 5, 3, 1, 1, 6, 7, 1, 1, 1, 1, 5, 1, 1, 14, 1, 1, 12, 102, 2, 9
OFFSET
1,3
LINKS
FORMULA
a(n) = gcd(A326049(n), A326050(n)) = gcd(n-A050449(n), A082052(n)-n).
a(2n-1) = A326047(2n-1) for all n.
PROG
(PARI)
A050449(n) = sumdiv(n, d, d*((d % 4) == 1)); \\ From A050449
A326049(n) = (n-A050449(n));
A082052(n) = sumdiv(n, d, if(1!=(d%4), d));
A326050(n) = (A082052(n)-n);
A326048(n) = gcd(A326049(n), A326050(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 04 2019
STATUS
approved