A386319 - cp's OEIS frontend

A386319 Triangle read by rows where row n is the start, corner and end vertex numbers of a triangular spiral with n sides on a triangular grid, starting from 1 and working inwards (0 <= k <= n).

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	3
6	1
7	3
8	5
9	6
10	1
11	4
12	7
13	9
14	10
15	1
16	5
17	9
18	12
19	14
20	15
21	1
22	6
23	11
24	15
25	18
26	20
27	21
28	1
29	7
30	13
31	18
32	22
33	25
34	27
35	28
36	1
37	8
38	15
39	21
40	26
41	30
42	33
43	35
44	36
45	1
46	9
47	17
48	24
49	30
50	35
51	39
52	42
53	44
54	45
55	1
56	10
57	19
58	27
59	34
60	40
61	45
62	49
63	52
64	54
65	55
66	1
67	11
68	21
69	30
70	38
71	45
72	51
73	56
74	60
75	63
76	65
77	66
78	1
79	12
80	23
81	33
82	42
83	50
84	57
85	63
86	68
87	72
88	75
89	77
90	78

[1, 1, 1, 1, 2, 3, 1, 3, 5, 6, 1, 4, 7, 9, 10, 1, 5, 9, 12, 14, 15, 1, 6, 11, 15, 18, 20, 21, 1, 7, 13, 18, 22, 25, 27, 28, 1, 8, 15, 21, 26, 30, 33, 35, 36, 1, 9, 17, 24, 30, 35, 39, 42, 44, 45, 1, 10, 19, 27, 34, 40, 45, 49, 52, 54, 55, 1, 11, 21, 30, 38, 45, 51, 56, 60, 63, 65, 66, 1, 12, 23, 33, 42, 50, 57, 63, 68, 72, 75, 77, 78]

cp's OEIS Frontend

A386319 Triangle read by rows where row n is the start, corner and end vertex numbers of a triangular spiral with n sides on a triangular grid, starting from 1 and working inwards (0 <= k <= n).

Table of values

List of values

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	3
6	1
7	3
8	5
9	6
10	1
11	4
12	7
13	9
14	10
15	1
16	5
17	9
18	12
19	14
20	15
21	1
22	6
23	11
24	15
25	18
26	20
27	21
28	1
29	7
30	13
31	18
32	22
33	25
34	27
35	28
36	1
37	8
38	15
39	21
40	26
41	30
42	33
43	35
44	36
45	1
46	9
47	17
48	24
49	30
50	35
51	39
52	42
53	44
54	45
55	1
56	10
57	19
58	27
59	34
60	40
61	45
62	49
63	52
64	54
65	55
66	1
67	11
68	21
69	30
70	38
71	45
72	51
73	56
74	60
75	63
76	65
77	66
78	1
79	12
80	23
81	33
82	42
83	50
84	57
85	63
86	68
87	72
88	75
89	77
90	78

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	3
6	1
7	3
8	5
9	6
10	1
11	4
12	7
13	9
14	10
15	1
16	5
17	9
18	12
19	14
20	15
21	1
22	6
23	11
24	15
25	18
26	20
27	21
28	1
29	7
30	13
31	18
32	22
33	25
34	27
35	28
36	1
37	8
38	15
39	21
40	26
41	30
42	33
43	35
44	36
45	1
46	9
47	17
48	24
49	30
50	35
51	39
52	42
53	44
54	45
55	1
56	10
57	19
58	27
59	34
60	40
61	45
62	49
63	52
64	54
65	55
66	1
67	11
68	21
69	30
70	38
71	45
72	51
73	56
74	60
75	63
76	65
77	66
78	1
79	12
80	23
81	33
82	42
83	50
84	57
85	63
86	68
87	72
88	75
89	77
90	78

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	3
6	1
7	3
8	5
9	6
10	1
11	4
12	7
13	9
14	10
15	1
16	5
17	9
18	12
19	14
20	15
21	1
22	6
23	11
24	15
25	18
26	20
27	21
28	1
29	7
30	13
31	18
32	22
33	25
34	27
35	28
36	1
37	8
38	15
39	21
40	26
41	30
42	33
43	35
44	36
45	1
46	9
47	17
48	24
49	30
50	35
51	39
52	42
53	44
54	45
55	1
56	10
57	19
58	27
59	34
60	40
61	45
62	49
63	52
64	54
65	55
66	1
67	11
68	21
69	30
70	38
71	45
72	51
73	56
74	60
75	63
76	65
77	66
78	1
79	12
80	23
81	33
82	42
83	50
84	57
85	63
86	68
87	72
88	75
89	77
90	78