A002817 - cp's OEIS frontend

A002817 Doubly triangular numbers: a(n) = n(n+1)(n^2+n+2)/8.

n	a(n)
0	0
1	1
2	6
3	21
4	55
5	120
6	231
7	406
8	666
9	1035
10	1540
11	2211
12	3081
13	4186
14	5565
15	7260
16	9316
17	11781
18	14706
19	18145
20	22155
21	26796
22	32131
23	38226
24	45150
25	52975
26	61776
27	71631
28	82621
29	94830
30	108345
31	123256
32	139656
33	157641
34	177310
35	198765
36	222111
37	247456
38	274911
39	304590

[0, 1, 6, 21, 55, 120, 231, 406, 666, 1035, 1540, 2211, 3081, 4186, 5565, 7260, 9316, 11781, 14706, 18145, 22155, 26796, 32131, 38226, 45150, 52975, 61776, 71631, 82621, 94830, 108345, 123256, 139656, 157641, 177310, 198765, 222111, 247456, 274911, 304590]

cp's OEIS Frontend

A002817 Doubly triangular numbers: a(n) = n(n+1)(n^2+n+2)/8.

Table of values

List of values

cp's OEIS Frontend

A002817 Doubly triangular numbers: a(n) = n*(n+1)*(n^2+n+2)/8.

Table of values

List of values

A002817 Doubly triangular numbers: a(n) = n(n+1)(n^2+n+2)/8.