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A100196
Numbers of positive integer cubes <= n^2.
7
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
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
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