A343357 7-rough abundant numbers.

20169691981106018776756331, 21373852696395930345517903, 21975933054040886129898689, 23476198863254546445077041, 23782174126975753483041047, 23836908704943476736166573, 24137500239684251978741183, 24272002214551310731350839, 24955720586792192723783257, 24986334842265665051802619

Offset: 1

Author

David A. Corneth, Apr 12 2021

Keywords

• nonn

Comments

Each term has at least A001276(4) = 15 distinct prime factors and A108227(4) = 18 prime factors counted with multiplicity. - Jianing Song, Apr 13 2021

The smallest term with exactly 15 distinct prime factors is a(830) = 465709156638373299218537971 = 7^3 * 11^2 * 13^2 * 17^2 * 19 * 23 * ... * 61. - Jianing Song, Apr 14 2021

Examples

			k = 20169691981106018776756331 is in the sequence as its smallest prime factor is at least 7 and it is abundant as sigma(k) > 2*k.
		

Links

• David A. Corneth, Table of n, a(n) for n = 1..2187

Crossrefs

Cf. A005101, A007775, A047802, A115414.

Programs

PARI

is(n) = gcd(n, 30) == 1 && sigma(n) > 2*n