OFFSET
1,1
COMMENTS
Variant of A374965 with initial condition a(1) = 147. If a(1) is prime, the trajectory is: a(1), 2, 4, 9, ... and matches A374965 after the second term. It appears that for most composite a(1), the trajectories also converge towards A374965. This could be due to A050412(n) being small for many composite n.
a(1) = 147 is the first composite number where the trajectory appears not to converge towards A374965.
Other values of a(1) for which the trajectory converges to this sequence are: 295, 591, 1183, 2278, 2367, 3328, 4557, 4602, 4735, 5950, 6072, 6657, 7227, 9115, 9205, 9471, 9612, 9912, 9955, ...
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..7697
MATHEMATICA
Module[{n = 1}, NestList[If[n++; PrimeQ[#], Prime[n] - 1, 2*# + 1] &, 147, 50]] (* Paolo Xausa, Aug 02 2024 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Aug 01 2024
STATUS
approved