login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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. 2
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 (list; graph; refs; listen; history; text; internal format)
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 A173137 A212986

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified November 26 14:56 EST 2014. Contains 250079 sequences.