A320849 - cp's OEIS frontend

A320849 Number of 3-element subsets of [n] whose sum is a triangular number.

n	a(n)
3	1
4	1
5	3
6	5
7	8
8	12
9	16
10	22
11	29
12	37
13	46
14	57
15	69
16	82
17	97
18	114
19	131
20	150
21	171
22	194
23	219
24	245
25	273
26	302
27	334
28	368
29	404
30	441
31	480
32	522
33	567
34	613
35	660
36	710
37	762
38	818
39	876
40	936
41	997
42	1061
43	1127
44	1196
45	1268
46	1342
47	1419
48	1498
49	1580
50	1664
51	1751
52	1841
53	1934
54	2029
55	2127

[1, 1, 3, 5, 8, 12, 16, 22, 29, 37, 46, 57, 69, 82, 97, 114, 131, 150, 171, 194, 219, 245, 273, 302, 334, 368, 404, 441, 480, 522, 567, 613, 660, 710, 762, 818, 876, 936, 997, 1061, 1127, 1196, 1268, 1342, 1419, 1498, 1580, 1664, 1751, 1841, 1934, 2029, 2127]

cp's OEIS Frontend

A320849 Number of 3-element subsets of [n] whose sum is a triangular number.

Table of values

List of values