login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A299016 Integer radii of circles over an integer lattice such that the number of unit squares whose centers are contained in the circle is less than the area of the circle. 0

%I

%S 2,6,12,19,24,36,40,43,48,52,53,55,60,61,65,70,74,77,89,91,108,111,

%T 116,123,125,128,129,140,141,142,146,152,154,159,166,169,171,180,181,

%U 183,184,197,198,205,209,210,212,214,222

%N Integer radii of circles over an integer lattice such that the number of unit squares whose centers are contained in the circle is less than the area of the circle.

%e For the circle with radius a(1) = 2, the point (3/2, 3/2 ), i.e. the center of the unit square bounded by x = 1, x = 2, y = 1, y = 2, is outside the circle of radius 2 centered at the origin so there are 12 unit squares with centers inside the circle of radius 2, and 12 < Pi *2 *2.

%t t = {}; For[n = 1, n < 223, n++, cnt = 0; For[x = -n, x < 0, x++, For[y = -n, y < 0, y++, If[N[Norm[{x + 1/2, y + 1/2}]] < n, cnt++]]] If[Pi*n*n > 4*cnt, t = Append[t, n]]] Print[t];

%K nonn

%O 1,1

%A _Dimitri Papadopoulos_, Jun 19 2018

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 19 15:13 EST 2022. Contains 350466 sequences. (Running on oeis4.)