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

Author

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

Keywords

• nonn

Examples

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

Crossrefs

Cf. A057671.

Programs

PARI

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

Formula

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

Extensions

Edited and extended by James Sellers, Oct 20 2000