A336352 Number of prime divisors of sigma(n) that are larger than the largest prime factor of n; a(1) = 0.

0, 1, 0, 1, 0, 0, 0, 2, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 2, 0, 0, 0, 0, 0

Offset

1,8

Links

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

Index entries for sequences related to sigma(n)

Formula

For all n >= 1, a(n) <= A058062(n).

Prog

(PARI) A336352(n) = if(1==n, 0, my(gp=vecmax(factor(n)[, 1])); #select(p -> (p>gp), factor(sigma(n))[, 1]));

Crossrefs

Cf. A000203, A006530, A058062, A336353 (positions of zeros).

Sequence in context: A304685 A186714 A160382 * A081221 A366988 A280827

Adjacent sequences: A336349 A336350 A336351 * A336353 A336354 A336355

Keyword

nonn

Author

Antti Karttunen, Jul 19 2020

Status

approved