A340070 a(n) = gcd(A003415(n), A069359(n)).

0, 1, 1, 2, 1, 5, 1, 4, 3, 7, 1, 2, 1, 9, 8, 8, 1, 3, 1, 2, 10, 13, 1, 4, 5, 15, 9, 2, 1, 31, 1, 16, 14, 19, 12, 30, 1, 21, 16, 4, 1, 41, 1, 2, 3, 25, 1, 8, 7, 5, 20, 2, 1, 9, 16, 4, 22, 31, 1, 2, 1, 33, 3, 32, 18, 61, 1, 2, 26, 59, 1, 12, 1, 39, 5, 2, 18, 71, 1, 8, 27, 43, 1, 2, 22, 45, 32, 4, 1, 3, 20, 2, 34, 49, 24

Offset

1,4

Links

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

Formula

a(n) = gcd(A003415(n), A069359(n)) = gcd(A003415(n), A329039(n)).

For all squarefree k, a(k) = A003415(k) = A069359(k).

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A069359(n) = (n*sumdiv(n, d, isprime(d)/d)); \\ From A069359
A340070(n) = gcd(A003415(n), A069359(n));

Crossrefs

Cf. A003415, A005117, A069359, A329039.

Cf. also A085731, A300253, A327858.

Sequence in context: A348495 A249274 A205443 * A069359 A318320 A369741

Adjacent sequences: A340067 A340068 A340069 * A340071 A340072 A340073

Keyword

nonn

Author

Antti Karttunen, Dec 30 2020

Status

approved