A248969 - cp's OEIS frontend

A248969 Start with a single equilateral triangle; at odd n-th generation add a similar triangle at each expandable vertex (this is the "vertex to vertex" version); alternate with the "side to vertex" version for even n-th generation; a(n) is the number of triangle for each generation.

n	a(n)
0	1
1	3
2	6
3	15
4	18
5	42
6	24
7	57
8	30
9	72
10	36
11	87
12	48
13	114
14	54
15	129
16	60
17	144
18	66
19	159
20	78
21	186
22	84
23	201
24	90
25	216
26	96
27	231
28	108
29	258
30	114
31	273
32	120
33	288
34	126
35	303
36	138
37	330
38	144
39	345
40	150
41	360
42	156
43	375
44	168
45	402
46	174
47	417
48	180
49	432
50	186
51	447
52	198
53	474
54	204
55	489
56	210
57	504
58	216
59	519

[1, 3, 6, 15, 18, 42, 24, 57, 30, 72, 36, 87, 48, 114, 54, 129, 60, 144, 66, 159, 78, 186, 84, 201, 90, 216, 96, 231, 108, 258, 114, 273, 120, 288, 126, 303, 138, 330, 144, 345, 150, 360, 156, 375, 168, 402, 174, 417, 180, 432, 186, 447, 198, 474, 204, 489, 210, 504, 216, 519]

cp's OEIS Frontend

A248969 Start with a single equilateral triangle; at odd n-th generation add a similar triangle at each expandable vertex (this is the "vertex to vertex" version); alternate with the "side to vertex" version for even n-th generation; a(n) is the number of triangle for each generation.

Table of values

List of values

n	a(n)
0	1
1	3
2	6
3	15
4	18
5	42
6	24
7	57
8	30
9	72
10	36
11	87
12	48
13	114
14	54
15	129
16	60
17	144
18	66
19	159
20	78
21	186
22	84
23	201
24	90
25	216
26	96
27	231
28	108
29	258
30	114
31	273
32	120
33	288
34	126
35	303
36	138
37	330
38	144
39	345
40	150
41	360
42	156
43	375
44	168
45	402
46	174
47	417
48	180
49	432
50	186
51	447
52	198
53	474
54	204
55	489
56	210
57	504
58	216
59	519

n	a(n)
0	1
1	3
2	6
3	15
4	18
5	42
6	24
7	57
8	30
9	72
10	36
11	87
12	48
13	114
14	54
15	129
16	60
17	144
18	66
19	159
20	78
21	186
22	84
23	201
24	90
25	216
26	96
27	231
28	108
29	258
30	114
31	273
32	120
33	288
34	126
35	303
36	138
37	330
38	144
39	345
40	150
41	360
42	156
43	375
44	168
45	402
46	174
47	417
48	180
49	432
50	186
51	447
52	198
53	474
54	204
55	489
56	210
57	504
58	216
59	519

n	a(n)
0	1
1	3
2	6
3	15
4	18
5	42
6	24
7	57
8	30
9	72
10	36
11	87
12	48
13	114
14	54
15	129
16	60
17	144
18	66
19	159
20	78
21	186
22	84
23	201
24	90
25	216
26	96
27	231
28	108
29	258
30	114
31	273
32	120
33	288
34	126
35	303
36	138
37	330
38	144
39	345
40	150
41	360
42	156
43	375
44	168
45	402
46	174
47	417
48	180
49	432
50	186
51	447
52	198
53	474
54	204
55	489
56	210
57	504
58	216
59	519