Number of surviving Collatz residues mod 2^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =4a(6) =8a(7) =13a(8) =19a(9) =38a(10) =64a(11) =128a(12) =226a(13) =367a(14) =734a(15) =1295a(16) =2114a(17) =4228a(18) =7495a(19) =14990a(20) =27328a(21) =46611a(22) =93222a(23) =168807a(24) =286581a(25) =573162a(26) =1037374a(27) =1762293a(28) =3524586a(29) =6385637