A227327 - cp's OEIS frontend

A227327 Number of non-equivalent ways to choose two points in an equilateral triangle grid of side n.

n	a(n)
1	0
2	1
3	4
4	10
5	22
6	41
7	72
8	116
9	180
10	265
11	380
12	526
13	714
14	945
15	1232
16	1576
17	1992
18	2481
19	3060
20	3730
21	4510
22	5401
23	6424
24	7580
25	8892
26	10361
27	12012
28	13846
29	15890
30	18145
31	20640
32	23376
33	26384
34	29665
35	33252
36	37146
37	41382
38	45961
39	50920
40	56260
41	62020
42	68201
43	74844

[0, 1, 4, 10, 22, 41, 72, 116, 180, 265, 380, 526, 714, 945, 1232, 1576, 1992, 2481, 3060, 3730, 4510, 5401, 6424, 7580, 8892, 10361, 12012, 13846, 15890, 18145, 20640, 23376, 26384, 29665, 33252, 37146, 41382, 45961, 50920, 56260, 62020, 68201, 74844]

cp's OEIS Frontend

A227327 Number of non-equivalent ways to choose two points in an equilateral triangle grid of side n.

Table of values

List of values