A077368 - OEIS

A077368 as a simple table

n	a(n)
1	0
2	1
3	3
4	6
5	10
6	15
7	21
8	28
9	36
10	45
11	55
12	66
13	78
14	91
15	105
16	231
17	435
18	465
19	666
20	1035
21	2211
22	3916
23	4005
24	6216
25	6786
26	19900
27	41905
28	46665
29	48205
30	162165
31	171405
32	200661
33	222111
34	329266
35	400065
36	1057785
37	1646205
38	2003001
39	2318781
40	2943951
41	10628355

[0,1,3,6,10,15,21,28,36,45,55,66,78,91,105,231, 435,465,666,1035,2211,3916,4005,6216,6786,19900, 41905,46665,48205,162165,171405,200661,222111, 329266,400065,1057785,1646205,2003001,2318781, 2943951,10628355]