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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 Table of n, a(n) for n=1..52. 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 Cf. A302829, A303644, A303646. Sequence in context: A081245 A010859 A291522 * A278830 A040381 A354569 Adjacent sequences: A303639 A303640 A303641 * A303643 A303644 A303645 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.)