Trajectory of 3 under map n->27n+1 if n odd, n->n/2 if n even.

Terms

a(0) =3a(1) =82a(2) =41a(3) =1108a(4) =554a(5) =277a(6) =7480a(7) =3740a(8) =1870a(9) =935a(10) =25246a(11) =12623a(12) =340822a(13) =170411a(14) =4601098a(15) =2300549a(16) =62114824a(17) =31057412a(18) =15528706a(19) =7764353a(20) =209637532a(21) =104818766a(22) =52409383a(23) =1415053342a(24) =707526671a(25) =19103220118