A268288 - cp's OEIS frontend

A268288 a(n) begins the first chain of 9 consecutive positive integers of h-values with symmetrical gaps about the center, where h(k) is the length of the finite sequence k, f(k), f(f(k)), ...., 1 in the Collatz (or 3x + 1) problem.

n	a(n)
1	1680
2	1991
3	2987
4	2988
5	2989
6	2990
7	2991
8	2992
9	3982
10	3983
11	3984
12	3985
13	3986
14	4722
15	4723
16	5313
17	5314
18	5315
19	5316
20	5317
21	6576
22	6577
23	6578
24	7083
25	7084
26	7085
27	7086
28	7087
29	7088
30	7089
31	7090
32	7091
33	7794
34	7795
35	7976
36	7977
37	7978
38	7979
39	7980
40	7981
41	8769
42	8770
43	8771

[1680, 1991, 2987, 2988, 2989, 2990, 2991, 2992, 3982, 3983, 3984, 3985, 3986, 4722, 4723, 5313, 5314, 5315, 5316, 5317, 6576, 6577, 6578, 7083, 7084, 7085, 7086, 7087, 7088, 7089, 7090, 7091, 7794, 7795, 7976, 7977, 7978, 7979, 7980, 7981, 8769, 8770, 8771]

cp's OEIS Frontend

A268288 a(n) begins the first chain of 9 consecutive positive integers of h-values with symmetrical gaps about the center, where h(k) is the length of the finite sequence k, f(k), f(f(k)), ...., 1 in the Collatz (or 3x + 1) problem.

Table of values

List of values