A135607 Floor of the area of a circle in terms of its circumference n.

0, 0, 0, 0, 1, 1, 2, 3, 5, 6, 7, 9, 11, 13, 15, 17, 20, 22, 25, 28, 31, 35, 38, 42, 45, 49, 53, 58, 62, 66, 71, 76, 81, 86, 91, 97, 103, 108, 114, 121, 127, 133, 140, 147, 154, 161, 168, 175, 183, 191, 198, 206, 215, 223, 232, 240, 249, 258, 267, 277, 286, 296, 305, 315

Offset

0,7

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Formula

Area of a circle of radius r is A = Pi*r^2. Circumference of a circle of radius r is n = 2*Pi*r. Then area in terms of the circumference n is A = n^2/(4*Pi).

Example

For a circle of circumference 10, the floor of the area A = floor(100/4/Pi) = 7.

Mathematica

Table[Floor[n^2/(4*Pi)], {n, 0, 25}] (* G. C. Greubel, Oct 21 2016 *)

Prog

(PARI) g(n) = for(c=0, n, a=c^2/4/Pi; print1(floor(a)", "))
(PARI) a(n) = n^2\(4*Pi); \\ Michel Marcus, Oct 22 2016

Crossrefs

Cf. A038130, A066643, A135039.

Sequence in context: A245395 A347498 A023884 * A376471 A358221 A026453

Adjacent sequences: A135604 A135605 A135606 * A135608 A135609 A135610

Keyword

nonn

Author

Cino Hilliard, Feb 27 2008

Status

approved