cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

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

Original entry on oeis.org

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

Views

Author

M. F. Hasler, Mar 26 2012

Keywords

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)

A322615 Nearest integer to 4*Pi*n^2.

Original entry on oeis.org

0, 13, 50, 113, 201, 314, 452, 616, 804, 1018, 1257, 1521, 1810, 2124, 2463, 2827, 3217, 3632, 4072, 4536, 5027, 5542, 6082, 6648, 7238, 7854, 8495, 9161, 9852, 10568, 11310, 12076, 12868, 13685, 14527, 15394, 16286, 17203, 18146, 19113, 20106, 21124, 22167
Offset: 0

Views

Author

Felix Fröhlich, Dec 20 2018

Keywords

Comments

Surface area of a sphere of radius n, rounded to the nearest integer.

Links

Crossrefs

Cf. A002101, A075726, A075727.

Programs

  • Maple
    a:=n->4*Pi*n^2: seq(round(a(n)),n=0..45); # Muniru A Asiru, Dec 20 2018
  • PARI
    a(n) = round(4*Pi*n^2)
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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