A057672 a(n) equals floor(As(n) - Ac(n)), where As(n) is the area of the square with side length n and Ac(n) is the area of the circle of diameter n.

0, 0, 1, 3, 5, 7, 10, 13, 17, 21, 25, 30, 36, 42, 48, 54, 62, 69, 77, 85, 94, 103, 113, 123, 134, 145, 156, 168, 180, 193, 206, 219, 233, 248, 262, 278, 293, 309, 326, 343, 360, 378, 396, 415, 434, 454, 474, 494, 515, 536, 558, 580, 602, 625, 649, 672, 697, 721, 747, 772, 798

Offset

1,4

Links

Table of n, a(n) for n=1..61.

Formula

a(n) = floor(n^2*(1-Pi/4)).

Example

a(7)=10 since floor(7^2(1-Pi/4)) = 10.

Prog

(PARI) a(n)=floor(n^2*(1-Pi/4)); \\ Michel Marcus, Sep 05 2014

Crossrefs

Cf. A057671.

Sequence in context: A077000 A195311 A184013 * A112509 A296846 A173137

Adjacent sequences: A057669 A057670 A057671 * A057673 A057674 A057675

Keyword

nonn

Author

seiringer.flor(AT)eudoramail.com, Oct 18 2000

Extensions

Edited and extended by James A. Sellers, Oct 20 2000

Status

approved