A056761 Odd numbers less than the cube of their number of divisors.

3, 5, 7, 9, 15, 21, 25, 27, 33, 35, 39, 45, 51, 55, 57, 63, 75, 81, 99, 105, 117, 135, 147, 153, 165, 171, 175, 189, 195, 207, 225, 231, 255, 273, 285, 297, 315, 345, 351, 357, 375, 385, 399, 405, 429, 435, 441, 455, 459, 465, 483, 495, 525, 567, 585, 675, 693

Offset: 1

Author

Labos Elemer, Aug 16 2000

Keywords

• fini
• full
• nonn

Comments

Last term is a(267) = 883575, confirming the author's conjecture. - Charles R Greathouse IV, Apr 27 2011

Examples

			14175 = 81*25*7 has 30 divisors, and 30^3 = 27000 > 14175.
		

Links

• Zak Seidov, Table of n, a(n) for n = 1..267 (complete sequence)

Crossrefs

Cf. A035033-A035035, A034884, A000005, A000265, A056757-A056767, A056781.

Programs

Mathematica

Select[Range[1, 10^6 + 1, 2], DivisorSigma[0, #]^3 > # &] (* Michael De Vlieger, Oct 26 2017 *)

PARI

isok(n) = (n % 2) && (numdiv(n)^3 > n); \\ Michel Marcus, Dec 19 2013