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.

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

Author

Antti Karttunen, Jun 04 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A050449, A082052, A326047, A326049, A326050.

Cf. also A009194, A325385, A325813, A325975.

Programs

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));

Formula

a(n) = gcd(A326049(n), A326050(n)) = gcd(n-A050449(n), A082052(n)-n).

a(2n-1) = A326047(2n-1) for all n.