

A303642


a(n) is the number of lattice points in Cartesian grid between circle of radius n and its inscribed square. The sides of the square are parallel to coordinate axes.


6



0, 0, 0, 20, 20, 28, 64, 72, 80, 80, 148, 148, 156, 248, 256, 264, 264, 380, 396, 404, 528, 552, 560, 700, 716, 740, 764, 928, 936, 960, 1148, 1180, 1196, 1212, 1440, 1448, 1472, 1700, 1740, 1764, 2000, 2040, 2064, 2104, 2380, 2396, 2428, 2720, 2760, 2784, 2832, 3156
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OFFSET

1,4


COMMENTS

If the sides of the inscribed square are parallel to bisector of coordinate axes we have a different sequence.


LINKS



PROG

(Python)
import math
for n in range(1, 100):
.count = 0
.for x in range(0, n):
..for y in range(n, n):
...if (x * x + y * y < n * n and x > n / math.sqrt(2)):
....count = count + 1
.print(4 * count)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



