Position of first appearance of n in A256757.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =19a(5) =47a(6) =163a(7) =487a(8) =1307a(9) =2879a(10) =19683a(11) =59049a(12) =177147a(13) =531441a(14) =1594323a(15) =4782969a(16) =14348907a(17) =43046721a(18) =86093443a(19) =344373773a(20) =688747547a(21) =3486784401