A347365 - cp's OEIS frontend

A347365 a(n) = n * (2-(-1)^n), or zero together with first differences of even triangular numbers halved (A074378).

n	a(n)
0	0
1	3
2	2
3	9
4	4
5	15
6	6
7	21
8	8
9	27
10	10
11	33
12	12
13	39
14	14
15	45
16	16
17	51
18	18
19	57
20	20
21	63
22	22
23	69
24	24
25	75
26	26
27	81
28	28
29	87
30	30
31	93
32	32
33	99
34	34
35	105
36	36
37	111
38	38
39	117
40	40
41	123
42	42
43	129
44	44
45	135
46	46
47	141
48	48
49	147
50	50
51	153
52	52
53	159
54	54
55	165
56	56
57	171
58	58
59	177
60	60
61	183
62	62
63	189
64	64

[0, 3, 2, 9, 4, 15, 6, 21, 8, 27, 10, 33, 12, 39, 14, 45, 16, 51, 18, 57, 20, 63, 22, 69, 24, 75, 26, 81, 28, 87, 30, 93, 32, 99, 34, 105, 36, 111, 38, 117, 40, 123, 42, 129, 44, 135, 46, 141, 48, 147, 50, 153, 52, 159, 54, 165, 56, 171, 58, 177, 60, 183, 62, 189, 64]

cp's OEIS Frontend

A347365 a(n) = n * (2-(-1)^n), or zero together with first differences of even triangular numbers halved (A074378).

Table of values

List of values

n	a(n)
0	0
1	3
2	2
3	9
4	4
5	15
6	6
7	21
8	8
9	27
10	10
11	33
12	12
13	39
14	14
15	45
16	16
17	51
18	18
19	57
20	20
21	63
22	22
23	69
24	24
25	75
26	26
27	81
28	28
29	87
30	30
31	93
32	32
33	99
34	34
35	105
36	36
37	111
38	38
39	117
40	40
41	123
42	42
43	129
44	44
45	135
46	46
47	141
48	48
49	147
50	50
51	153
52	52
53	159
54	54
55	165
56	56
57	171
58	58
59	177
60	60
61	183
62	62
63	189
64	64

n	a(n)
0	0
1	3
2	2
3	9
4	4
5	15
6	6
7	21
8	8
9	27
10	10
11	33
12	12
13	39
14	14
15	45
16	16
17	51
18	18
19	57
20	20
21	63
22	22
23	69
24	24
25	75
26	26
27	81
28	28
29	87
30	30
31	93
32	32
33	99
34	34
35	105
36	36
37	111
38	38
39	117
40	40
41	123
42	42
43	129
44	44
45	135
46	46
47	141
48	48
49	147
50	50
51	153
52	52
53	159
54	54
55	165
56	56
57	171
58	58
59	177
60	60
61	183
62	62
63	189
64	64

n	a(n)
0	0
1	3
2	2
3	9
4	4
5	15
6	6
7	21
8	8
9	27
10	10
11	33
12	12
13	39
14	14
15	45
16	16
17	51
18	18
19	57
20	20
21	63
22	22
23	69
24	24
25	75
26	26
27	81
28	28
29	87
30	30
31	93
32	32
33	99
34	34
35	105
36	36
37	111
38	38
39	117
40	40
41	123
42	42
43	129
44	44
45	135
46	46
47	141
48	48
49	147
50	50
51	153
52	52
53	159
54	54
55	165
56	56
57	171
58	58
59	177
60	60
61	183
62	62
63	189
64	64