A181995 - cp's OEIS frontend

A181995 a(n) = if n mod 2 = 1 then n*(n - 1) else (n - 1)^2 + (n - 2)/2.

n	a(n)
0	0
1	0
2	1
3	6
4	10
5	20
6	27
7	42
8	52
9	72
10	85
11	110
12	126
13	156
14	175
15	210
16	232
17	272
18	297
19	342
20	370
21	420
22	451
23	506
24	540
25	600
26	637
27	702
28	742
29	812
30	855
31	930
32	976
33	1056
34	1105
35	1190
36	1242
37	1332
38	1387
39	1482
40	1540
41	1640
42	1701
43	1806
44	1870
45	1980
46	2047
47	2162
48	2232
49	2352
50	2425
51	2550
52	2626
53	2756
54	2835
55	2970
56	3052
57	3192
58	3277
59	3422
60	3510
61	3660
62	3751
63	3906
64	4000
65	4160
66	4257
67	4422

[0, 0, 1, 6, 10, 20, 27, 42, 52, 72, 85, 110, 126, 156, 175, 210, 232, 272, 297, 342, 370, 420, 451, 506, 540, 600, 637, 702, 742, 812, 855, 930, 976, 1056, 1105, 1190, 1242, 1332, 1387, 1482, 1540, 1640, 1701, 1806, 1870, 1980, 2047, 2162, 2232, 2352, 2425, 2550, 2626, 2756, 2835, 2970, 3052, 3192, 3277, 3422, 3510, 3660, 3751, 3906, 4000, 4160, 4257, 4422]

cp's OEIS Frontend

A181995 a(n) = if n mod 2 = 1 then n*(n - 1) else (n - 1)^2 + (n - 2)/2.

Table of values

List of values