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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
2, 6, 12, 19, 24, 36, 40, 43, 48, 52, 53, 55, 60, 61, 65, 70, 74, 77, 89, 91, 108, 111, 116, 123, 125, 128, 129, 140, 141, 142, 146, 152, 154, 159, 166, 169, 171, 180, 181, 183, 184, 197, 198, 205, 209, 210, 212, 214, 222 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..49.

EXAMPLE

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.

MATHEMATICA

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];

CROSSREFS

Sequence in context: A053660 A104969 A065005 * A347472 A340663 A139084

Adjacent sequences:  A299013 A299014 A299015 * A299017 A299018 A299019

KEYWORD

nonn

AUTHOR

Dimitri Papadopoulos, Jun 19 2018

STATUS

approved

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Last modified November 30 17:12 EST 2021. Contains 349424 sequences. (Running on oeis4.)