A326923 - cp's OEIS frontend

A326923 a(n) is the number of iterations needed to reach 1 or 9 starting at n and using the map k -> (k/2 if k is even, otherwise k + (largest triangular number < k)). Set a(n) = -1 if the trajectory never reaches 1 or 9.

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

[0, 1, 3, 2, 4, 4, 9, 3, 0, 5, 4, 5, 8, 10, 10, 4, 6, 1, 8, 6, 3, 5, 7, 6, 9, 9, 8, 11, 15, 11, 17, 5, 19, 7, 19, 2, 27, 9, 41, 7, 33, 4, 39, 6, 47, 8, 10, 7, 12, 10, 9, 10, 14, 9, 12, 12, 14, 16, 16, 12, 18, 18, 18, 6, 14, 20, 26, 8, 32, 20, 24, 3, 26, 28, 40, 10, 32]

cp's OEIS Frontend

A326923 a(n) is the number of iterations needed to reach 1 or 9 starting at n and using the map k -> (k/2 if k is even, otherwise k + (largest triangular number < k)). Set a(n) = -1 if the trajectory never reaches 1 or 9.

Table of values

List of values

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

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

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