A261955 - cp's OEIS frontend

A261955 Start with a single equilateral triangle for n=0; for the odd n-th generation add a triangle at each expandable side of the triangles of the (n-1)-th generation (this is the "side to side" version); for the even n-th generation use the "vertex to side" version; a(n) is the number of triangles added in the n-th generation.

n	a(n)
0	1
1	3
2	6
3	15
4	12
5	24
6	15
7	33
8	21
9	45
10	39
11	72
12	36
13	78
14	39
15	87
16	45
17	99
18	63
19	126
20	60
21	132
22	63
23	141
24	69
25	153
26	87
27	180
28	84
29	186
30	87
31	195
32	93
33	207
34	111
35	234
36	108
37	240
38	111
39	249
40	117
41	261
42	135
43	288
44	132
45	294
46	135
47	303
48	141
49	315
50	159

[1, 3, 6, 15, 12, 24, 15, 33, 21, 45, 39, 72, 36, 78, 39, 87, 45, 99, 63, 126, 60, 132, 63, 141, 69, 153, 87, 180, 84, 186, 87, 195, 93, 207, 111, 234, 108, 240, 111, 249, 117, 261, 135, 288, 132, 294, 135, 303, 141, 315, 159]

cp's OEIS Frontend

Table of values

List of values

n	a(n)
0	1
1	3
2	6
3	15
4	12
5	24
6	15
7	33
8	21
9	45
10	39
11	72
12	36
13	78
14	39
15	87
16	45
17	99
18	63
19	126
20	60
21	132
22	63
23	141
24	69
25	153
26	87
27	180
28	84
29	186
30	87
31	195
32	93
33	207
34	111
35	234
36	108
37	240
38	111
39	249
40	117
41	261
42	135
43	288
44	132
45	294
46	135
47	303
48	141
49	315
50	159

n	a(n)
0	1
1	3
2	6
3	15
4	12
5	24
6	15
7	33
8	21
9	45
10	39
11	72
12	36
13	78
14	39
15	87
16	45
17	99
18	63
19	126
20	60
21	132
22	63
23	141
24	69
25	153
26	87
27	180
28	84
29	186
30	87
31	195
32	93
33	207
34	111
35	234
36	108
37	240
38	111
39	249
40	117
41	261
42	135
43	288
44	132
45	294
46	135
47	303
48	141
49	315
50	159

n	a(n)
0	1
1	3
2	6
3	15
4	12
5	24
6	15
7	33
8	21
9	45
10	39
11	72
12	36
13	78
14	39
15	87
16	45
17	99
18	63
19	126
20	60
21	132
22	63
23	141
24	69
25	153
26	87
27	180
28	84
29	186
30	87
31	195
32	93
33	207
34	111
35	234
36	108
37	240
38	111
39	249
40	117
41	261
42	135
43	288
44	132
45	294
46	135
47	303
48	141
49	315
50	159