A344704 a(n) = gcd(A001615(n)-n, sigma(n)-(A001615(n)+n)).

1, 1, 1, 1, 1, 6, 1, 1, 1, 2, 1, 4, 1, 2, 3, 1, 1, 3, 1, 2, 1, 2, 1, 12, 1, 2, 1, 20, 1, 6, 1, 1, 3, 2, 1, 1, 1, 2, 1, 2, 1, 6, 1, 4, 3, 2, 1, 4, 1, 1, 3, 2, 1, 6, 1, 8, 1, 2, 1, 12, 1, 2, 11, 1, 1, 6, 1, 10, 3, 2, 1, 3, 1, 2, 1, 4, 1, 6, 1, 2, 1, 2, 1, 4, 1, 2, 3, 4, 1, 18, 7, 4, 1, 2, 5, 12, 1, 5, 3, 1, 1, 6, 1, 2, 3

Offset

1,6

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = gcd(A306927(n), n-A244963(n)) = gcd(A001615(n)-n, sigma(n)-(A001615(n)+n)).

Prog

(PARI)
A001615(n) = if(1==n, n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
A344704(n) = gcd(A001615(n)-n, sigma(n)-(A001615(n)+n));

Crossrefs

Cf. A000203, A001615, A244963, A306927, A344700, A344705.

Sequence in context: A333461 A325975 A325813 * A325633 A325640 A325632

Adjacent sequences: A344701 A344702 A344703 * A344705 A344706 A344707

Keyword

nonn

Author

Antti Karttunen, May 28 2021

Status

approved