A225729 Numbers n such that n < d(n)^(21/10), where d(n) is the number of divisors of n.

2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 90, 96, 100, 108, 112, 120, 126, 132, 140, 144, 150, 156, 160, 168, 180, 192, 210, 216, 240, 252, 264, 270, 280, 288, 300, 312, 330, 336, 360, 396

Offset: 1

Author

T. D. Noe, May 14 2013

Keywords

• nonn
• fini
• full

Comments

Alternatively, we could write n^10 < d(n)^21. The last odd number is a(10) = 15.

Links

• T. D. Noe, Table of n, a(n) for n = 1..89 (complete sequence)

Crossrefs

Cf. A034884 (n < d(n)^2), A175495 (n < 2^d(n)), A056757 (n < d(n)^3).

Cf. A225730-A225738.

Programs

Mathematica

t = {}; Do[If[n < DivisorSigma[0, n]^(21/10), AppendTo[t, n]], {n, 10^4}]; t