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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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
If the sides of the inscribed square are parallel to bisector of coordinate axes we have a different sequence.
LINKS
Kirill Ustyantsev, illustrated example
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
Sequence in context: A081245 A010859 A291522 * A278830 A040381 A354569
KEYWORD
nonn
AUTHOR
Kirill Ustyantsev, Apr 27 2018
EXTENSIONS
Offset corrected by Andrey Zabolotskiy, May 05 2018
STATUS
approved

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Last modified July 21 11:45 EDT 2024. Contains 374472 sequences. (Running on oeis4.)