A229037 - cp's OEIS frontend

A229037 The "forest fire": sequence of positive integers where each is chosen to be as small as possible subject to the condition that no three terms a(j), a(j+k), a(j+2k) (for any j and k) form an arithmetic progression.

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

[1, 1, 2, 1, 1, 2, 2, 4, 4, 1, 1, 2, 1, 1, 2, 2, 4, 4, 2, 4, 4, 5, 5, 8, 5, 5, 9, 1, 1, 2, 1, 1, 2, 2, 4, 4, 1, 1, 2, 1, 1, 2, 2, 4, 4, 2, 4, 4, 5, 5, 8, 5, 5, 9, 9, 4, 4, 5, 5, 10, 5, 5, 10, 2, 10, 13, 11, 10, 8, 11, 13, 10, 12, 10, 10, 12, 10, 11, 14, 20, 13]

cp's OEIS Frontend

A229037 The "forest fire": sequence of positive integers where each is chosen to be as small as possible subject to the condition that no three terms a(j), a(j+k), a(j+2k) (for any j and k) form an arithmetic progression.

Table of values

List of values

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

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

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