A213215 - cp's OEIS frontend

A213215 For the Collatz (3x+1) iterations starting with the odd numbers k, a(n) is the smallest k such that the trajectory contains at least n successive odd numbers == 3 (mod 4).

n	a(n)
1	1
2	3
3	7
4	15
5	27
6	27
7	127
8	255
9	511
10	1023
11	1819
12	4095
13	4255
14	16383
15	32767
16	65535
17	77671
18	262143
19	459759
20	1048575
21	2097151
22	4194303
23	7456539
24	16777215
25	33554431
26	67108863
27	125687199
28	125687199
29	125687199
30	1073741823
31	2147483647
32	4294967295
33	8589934591
34	17179869183

[1, 3, 7, 15, 27, 27, 127, 255, 511, 1023, 1819, 4095, 4255, 16383, 32767, 65535, 77671, 262143, 459759, 1048575, 2097151, 4194303, 7456539, 16777215, 33554431, 67108863, 125687199, 125687199, 125687199, 1073741823, 2147483647, 4294967295, 8589934591, 17179869183]

cp's OEIS Frontend

A213215 For the Collatz (3x+1) iterations starting with the odd numbers k, a(n) is the smallest k such that the trajectory contains at least n successive odd numbers == 3 (mod 4).

Table of values

List of values