A181944 - cp's OEIS frontend

A181944 Number of convex quadrilaterals, distinct up to congruence, on an n X n grid (or geoboard).

n	a(n)
1	0
2	1
3	12
4	89
5	407
6	1413
7	3894
8	9431
9	20212
10	39847
11	73177
12	127582
13	211012
14	337186
15	519594
16	777447
17	1134269
18	1620415
19	2264873
20	3114709
21	4209184
22	5609209
23	7378581
24	9594611
25	12326333
26	15688198
27	19779188
28	24721601
29	30646522
30	37727553
31	46093734
32	55983150
33	67558997

[0, 1, 12, 89, 407, 1413, 3894, 9431, 20212, 39847, 73177, 127582, 211012, 337186, 519594, 777447, 1134269, 1620415, 2264873, 3114709, 4209184, 5609209, 7378581, 9594611, 12326333, 15688198, 19779188, 24721601, 30646522, 37727553, 46093734, 55983150, 67558997]

cp's OEIS Frontend

A181944 Number of convex quadrilaterals, distinct up to congruence, on an n X n grid (or geoboard).

Table of values

List of values