Least number whose Collatz 3x+1 trajectory contains a number >= 2^n.

Terms

a(0) =1a(1) =2a(2) =3a(3) =3a(4) =3a(5) =7a(6) =15a(7) =15a(8) =27a(9) =27a(10) =27a(11) =27a(12) =27a(13) =27a(14) =447a(15) =447a(16) =703a(17) =703a(18) =1819a(19) =1819a(20) =1819a(21) =4255a(22) =4255a(23) =9663a(24) =9663a(25) =20895a(26) =26623a(27) =60975a(28) =60975a(29) =60975