A078373 - cp's OEIS frontend

A078373 n sets a record for the number of primes in {n, f(n), f(f(n)), ..., 1}, where f is the Collatz function defined by f(x) = x/2 if x is even; f(x) = 3x + 1 if x is odd.

n	a(n)
1	2
2	3
3	7
4	19
5	27
6	97
7	171
8	231
9	487
10	763
11	1071
12	4011
13	6171
14	10971
15	17647
16	47059
17	99151
18	117511
19	202471
20	260847
21	481959
22	963919
23	1564063
24	1805311
25	1993215
26	6991599
27	8400511
28	11200681
29	36791535
30	46564287
31	103359483
32	206718967
33	359502063

[2, 3, 7, 19, 27, 97, 171, 231, 487, 763, 1071, 4011, 6171, 10971, 17647, 47059, 99151, 117511, 202471, 260847, 481959, 963919, 1564063, 1805311, 1993215, 6991599, 8400511, 11200681, 36791535, 46564287, 103359483, 206718967, 359502063]

cp's OEIS Frontend

A078373 n sets a record for the number of primes in {n, f(n), f(f(n)), ..., 1}, where f is the Collatz function defined by f(x) = x/2 if x is even; f(x) = 3x + 1 if x is odd.

Table of values

List of values