A075034 Numbers n such that tau(n) >= tau(n+1) >= tau(n+2) where tau(n) = number of divisors of n.

20, 21, 32, 33, 44, 45, 56, 57, 75, 80, 81, 84, 85, 92, 93, 104, 105, 116, 117, 132, 135, 140, 141, 144, 147, 165, 170, 171, 176, 177, 189, 200, 201, 204, 212, 213, 216, 217, 224, 225, 230, 231, 242, 243, 252, 260, 261, 272, 285, 296, 297, 300, 301, 315, 324

Offset: 1

Author

Amarnath Murthy, Sep 02 2002

Keywords

• nonn

Links

• Karl V. Keller, Jr., Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005 (tau), A075032, A075033, A075035.

Programs

Mathematica

nn = 400; t = DivisorSigma[0, Range[nn]]; Select[Range[nn-2], t[[#]] >= t[[#+1]] >= t[[#+2]] &] (* Harvey P. Dale, May 24 2012 *)

Python

from sympy import divisor_count as tau
[n for n in range(1,333) if tau(n) >= tau(n+1) >= tau(n+2)] # Karl V. Keller, Jr., Jul 10 2020

Extensions

More terms from Benoit Cloitre, Sep 07 2002