OFFSET
1,1
EXAMPLE
305 is a term since its Collatz trajectory is 305, 916, 458, 229, 688, 344, 172, 86, 43, 130, 65, 196, 98, 49, 148, 74, 37, 112, 56, 28, 14, 7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1.
MATHEMATICA
q[n_] := Count[NestWhileList[If[OddQ[#], 3 # + 1, #/2] &, n, # > 1 &], _?OddQ] == 12; Select[Range[1, 2750, 2], q] (* Amiram Eldar, May 20 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Krishna Kumar Arumugam, May 20 2022
STATUS
approved