A351131 - cp's OEIS frontend

A351131 Triangular numbers (A000217) whose second arithmetic derivative (A068346) is also a triangular number.

n	a(n)
1	0
2	1
3	3
4	6
5	10
6	66
7	78
8	105
9	231
10	325
11	465
12	561
13	595
14	861
15	1378
16	2211
17	2278
18	2485
19	3081
20	3570
21	3655
22	4278
23	4465
24	5253
25	6441
26	6670
27	8515
28	8778
29	9453
30	9870
31	10011
32	10153
33	12561
34	13530
35	15051
36	18145
37	21115
38	21945
39	22578
40	23005
41	25878
42	27966
43	28441
44	40470
45	45753

[0, 1, 3, 6, 10, 66, 78, 105, 231, 325, 465, 561, 595, 861, 1378, 2211, 2278, 2485, 3081, 3570, 3655, 4278, 4465, 5253, 6441, 6670, 8515, 8778, 9453, 9870, 10011, 10153, 12561, 13530, 15051, 18145, 21115, 21945, 22578, 23005, 25878, 27966, 28441, 40470, 45753]

cp's OEIS Frontend

A351131 Triangular numbers (A000217) whose second arithmetic derivative (A068346) is also a triangular number.

Table of values

List of values