A320850 - cp's OEIS frontend

A320850 Number of 4-element subsets of [n] whose sum is a triangular number.

n	a(n)
4	1
5	1
6	3
7	6
8	11
9	20
10	32
11	48
12	70
13	98
14	132
15	174
16	226
17	287
18	359
19	444
20	542
21	655
22	783
23	928
24	1092
25	1275
26	1479
27	1707
28	1957
29	2231
30	2534
31	2865
32	3225
33	3617
34	4040
35	4497
36	4993
37	5527
38	6098
39	6710
40	7363
41	8062
42	8810
43	9605
44	10447
45	11342
46	12291
47	13295
48	14358
49	15478
50	16658
51	17904

[1, 1, 3, 6, 11, 20, 32, 48, 70, 98, 132, 174, 226, 287, 359, 444, 542, 655, 783, 928, 1092, 1275, 1479, 1707, 1957, 2231, 2534, 2865, 3225, 3617, 4040, 4497, 4993, 5527, 6098, 6710, 7363, 8062, 8810, 9605, 10447, 11342, 12291, 13295, 14358, 15478, 16658, 17904]

cp's OEIS Frontend

A320850 Number of 4-element subsets of [n] whose sum is a triangular number.

Table of values

List of values