A100196 Numbers of positive integer cubes <= n^2.

0, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 18, 18, 18

Offset

0,4

Links

Peter Munn, Table of n, a(n) for n = 0..10000

Formula

a(n) = floor(n^(2/3)). [Charles R Greathouse IV, Mar 21 2012]

Mathematica

Table[ Floor[n^(2/3)], {n, 120}] (* Ray Chandler, Jan 09 2005 *)

Prog

(PARI) a(n)=floor(sqrtn(n^2, 3)) \\ Charles R Greathouse IV, Mar 21 2012; corrected by Michel Marcus, Mar 08 2020
(PARI) a(n)=(n^2+.5)^(1/3)\1 \\ More careful rounding. - Charles R Greathouse IV, Mar 21 2012

Crossrefs

Cf. A000196, A054846, A062108, A100197.

Sequence in context: A028829 A130855 A235963 * A278078 A094708 A302931

Adjacent sequences: A100193 A100194 A100195 * A100197 A100198 A100199

Keyword

easy,nonn

Author

Giovanni Teofilatto, Dec 27 2004

Extensions

Corrected and extended by Ray Chandler, Jan 09 2005

a(0)=0 inserted by Sean A. Irvine, Jun 22 2020

Status

approved