Difference between 2^n and the next smaller or equal power of 3.

Terms

a(0) =0a(1) =1a(2) =1a(3) =5a(4) =7a(5) =5a(6) =37a(7) =47a(8) =13a(9) =269a(10) =295a(11) =1319a(12) =1909a(13) =1631a(14) =9823a(15) =13085a(16) =6487a(17) =72023a(18) =84997a(19) =347141a(20) =517135a(21) =502829a(22) =2599981a(23) =3605639a(24) =2428309a(25) =19205525a(26) =24062143a(27) =5077565a(28) =139295293a(29) =149450423