A303669 - cp's OEIS frontend

A303669 a(n) is the number of lattice points in a Cartesian grid between a circle of radius n, centered at the origin, and an inscribed equilateral triangle; one of the sides of triangle is perpendicular to X-axis.

n	a(n)
1	0
2	2
3	13
4	21
5	36
6	56
7	81
8	103
9	144
10	166
11	215
12	239
13	298
14	342
15	405
16	447
17	514
18	568
19	655
20	707
21	796
22	864
23	961
24	1019
25	1128
26	1208
27	1337
28	1405
29	1524
30	1614
31	1749
32	1847
33	1990
34	2082
35	2249
36	2333
37	2502
38	2600
39	2789
40	2899
41	3064
42	3192
43	3383
44	3519
45	3718
46	3832
47	4047
48	4175

[0, 2, 13, 21, 36, 56, 81, 103, 144, 166, 215, 239, 298, 342, 405, 447, 514, 568, 655, 707, 796, 864, 961, 1019, 1128, 1208, 1337, 1405, 1524, 1614, 1749, 1847, 1990, 2082, 2249, 2333, 2502, 2600, 2789, 2899, 3064, 3192, 3383, 3519, 3718, 3832, 4047, 4175]

cp's OEIS Frontend

A303669 a(n) is the number of lattice points in a Cartesian grid between a circle of radius n, centered at the origin, and an inscribed equilateral triangle; one of the sides of triangle is perpendicular to X-axis.

Table of values

List of values