A225733 Numbers n such that n < d(n)^(5/2), where d(n) is the number of divisors of n.

2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 26, 27, 28, 30, 32, 36, 40, 42, 44, 45, 48, 50, 52, 54, 56, 60, 63, 64, 66, 68, 70, 72, 75, 76, 78, 80, 84, 88, 90, 96, 100, 102, 104, 105, 108, 110, 112, 114, 120, 126, 128, 130, 132, 135, 136, 138

Offset: 1

Author

T. D. Noe, May 14 2013

Keywords

• nonn
• fini
• full

Comments

Alternatively, we could write n^2 < d(n)^5. The last odd number is a(206) = 945.

Links

• T. D. Noe, Table of n, a(n) for n = 1..1018 (complete sequence)

Crossrefs

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

Cf. A225729-A225738.

Programs

Mathematica

t = {}; Do[If[n < DivisorSigma[0, n]^(5/2), AppendTo[t, n]], {n, 10^6}]; t