A053458 - cp's OEIS frontend

A053458 Open disk numbers (version 3): a(n) is the number of points (i+j/2,j*sqrt(3)/2), i,j integers (triangular grid) contained in an open disk of diameter n, centered at (0,0).

n	a(n)
0	0
1	1
2	1
3	7
4	13
5	19
6	31
7	43
8	55
9	73
10	85
11	109
12	121
13	151
14	169
15	199
16	235
17	253
18	295
19	313
20	361
21	397
22	433
23	475
24	511
25	571
26	595
27	661
28	703
29	757
30	817
31	859
32	925
33	979
34	1039
35	1111
36	1159
37	1237
38	1285
39	1381
40	1453
41	1519
42	1597
43	1663
44	1759
45	1813
46	1915
47	1993
48	2077
49	2173
50	2257

[0, 1, 1, 7, 13, 19, 31, 43, 55, 73, 85, 109, 121, 151, 169, 199, 235, 253, 295, 313, 361, 397, 433, 475, 511, 571, 595, 661, 703, 757, 817, 859, 925, 979, 1039, 1111, 1159, 1237, 1285, 1381, 1453, 1519, 1597, 1663, 1759, 1813, 1915, 1993, 2077, 2173, 2257]

cp's OEIS Frontend

A053458 Open disk numbers (version 3): a(n) is the number of points (i+j/2,j*sqrt(3)/2), i,j integers (triangular grid) contained in an open disk of diameter n, centered at (0,0).

Table of values

List of values