A261954 - cp's OEIS frontend

A261954 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 "side to vertex" version; a(n) is the number of triangles added in the n-th generation.

n	a(n)
0	1
1	3
2	3
3	6
4	12
5	15
6	21
7	18
8	30
9	27
10	39
11	30
12	48
13	39
14	57
15	42
16	66
17	51
18	75
19	54
20	84
21	63
22	93
23	66
24	102
25	75
26	111
27	78
28	120
29	87
30	129
31	90
32	138
33	99
34	147
35	102
36	156
37	111
38	165
39	114
40	174
41	123
42	183
43	126
44	192
45	135
46	201
47	138
48	210
49	147
50	219

[1, 3, 3, 6, 12, 15, 21, 18, 30, 27, 39, 30, 48, 39, 57, 42, 66, 51, 75, 54, 84, 63, 93, 66, 102, 75, 111, 78, 120, 87, 129, 90, 138, 99, 147, 102, 156, 111, 165, 114, 174, 123, 183, 126, 192, 135, 201, 138, 210, 147, 219]

cp's OEIS Frontend

Table of values

List of values

n	a(n)
0	1
1	3
2	3
3	6
4	12
5	15
6	21
7	18
8	30
9	27
10	39
11	30
12	48
13	39
14	57
15	42
16	66
17	51
18	75
19	54
20	84
21	63
22	93
23	66
24	102
25	75
26	111
27	78
28	120
29	87
30	129
31	90
32	138
33	99
34	147
35	102
36	156
37	111
38	165
39	114
40	174
41	123
42	183
43	126
44	192
45	135
46	201
47	138
48	210
49	147
50	219

n	a(n)
0	1
1	3
2	3
3	6
4	12
5	15
6	21
7	18
8	30
9	27
10	39
11	30
12	48
13	39
14	57
15	42
16	66
17	51
18	75
19	54
20	84
21	63
22	93
23	66
24	102
25	75
26	111
27	78
28	120
29	87
30	129
31	90
32	138
33	99
34	147
35	102
36	156
37	111
38	165
39	114
40	174
41	123
42	183
43	126
44	192
45	135
46	201
47	138
48	210
49	147
50	219

n	a(n)
0	1
1	3
2	3
3	6
4	12
5	15
6	21
7	18
8	30
9	27
10	39
11	30
12	48
13	39
14	57
15	42
16	66
17	51
18	75
19	54
20	84
21	63
22	93
23	66
24	102
25	75
26	111
27	78
28	120
29	87
30	129
31	90
32	138
33	99
34	147
35	102
36	156
37	111
38	165
39	114
40	174
41	123
42	183
43	126
44	192
45	135
46	201
47	138
48	210
49	147
50	219