1,3

The colossally abundant numbers are a subset of the superabundant abundant numbers. Is there a formula for a(n) that depends on the two consecutive colossally abundant numbers A004490(n) and A004490(n+1)?

T. D. Noe, Table of n, a(n) for n=1..10000

a(3)=3 because between colossally abundant numbers 12 and 60 there are three superabundant numbers: 24, 36 and 48.

Cf. A004490 (colossally abundant numbers), A004394 (superabundant numbers), A189228 (superabundant numbers that are not colossally abundant).

Sequence in context: A245251 A177461 A201924 * A113069 A136163 A178313

Adjacent sequences: A112971 A112972 A112973 * A112975 A112976 A112977

nonn

T. D. Noe, Oct 07 2005

approved