Trajectory of 3 under map n->19n+1 if n odd, n->n/2 if n even.

Terms

a(0) =3a(1) =58a(2) =29a(3) =552a(4) =276a(5) =138a(6) =69a(7) =1312a(8) =656a(9) =328a(10) =164a(11) =82a(12) =41a(13) =780a(14) =390a(15) =195a(16) =3706a(17) =1853a(18) =35208a(19) =17604a(20) =8802a(21) =4401a(22) =83620a(23) =41810a(24) =20905a(25) =397196a(26) =198598a(27) =99299a(28) =1886682a(29) =943341