A263572 Numbers n that minimize sigma(n) / (n^(1-delta) d(n)) for some delta > 0, where d = divisor count = A000005, sigma = divisor sum = A000203.

1, 2, 6, 12, 60, 120, 360, 2520, 5040, 55440, 720720, 1441440, 4324320, 21621600, 367567200, 6983776800, 13967553600, 321253732800, 2248776129600, 65214507758400, 195643523275200, 6064949221531200, 12129898443062400, 448806242393308800, 18401055938125660800

Offset: 1

Author

William C. Jagy, Oct 21 2015

Keywords

• nonn

Comments

These are the miserable average divisor numbers. Similar to superior highly composite numbers (A002201) or colossally abundant numbers (A004490).

a(2)..a(26) are also the first 25 terms of A002201.

Links

• William C. Jagy, Table of n, a(n) for n = 1..93
• Mathematics Stack Exchange, Bounds on the average of the divisors of natural numbers

Crossrefs

Cf. A000005, A000203, A002201, A004490.