A210639 Nearest integer to (4/3)*Pi*n^(3/2).

0, 4, 12, 22, 34, 47, 62, 78, 95, 113, 132, 153, 174, 196, 219, 243, 268, 294, 320, 347, 375, 403, 432, 462, 492, 524, 555, 588, 621, 654, 688, 723, 758, 794, 830, 867, 905, 943, 981, 1020, 1060, 1100, 1140, 1181, 1223, 1264, 1307, 1350, 1393, 1437, 1481

Offset: 0

Author

M. F. Hasler, Mar 26 2012

Keywords

• nonn

Comments

Approximates the volume of the ball { (x,y,z) | x^2+y^2+z^2 < n }. Provides a more refined scale than A002101(n) = a(n^2).

Crossrefs

Cf. A000092 and references therein.

Programs

Mathematica

Table[Round[4/3*Pi* n^(3/2)],{n,0,50}] (* Harvey P. Dale, Aug 04 2020 *)

PARI

a(n)=round(4/3*Pi*n^1.5)