Tribonacci representation of 2^n, written in base 10.

Terms

a(0) =1a(1) =2a(2) =4a(3) =9a(4) =19a(5) =41a(6) =88a(7) =195a(8) =418a(9) =1033a(10) =2195a(11) =4705a(12) =10282a(13) =21850a(14) =49160a(15) =104465a(16) =223780a(17) =550294a(18) =1186344a(19) =2525345a(20) =5514438a(21) =11817057a(22) =26297040a(23) =56201282a(24) =138856076a(25) =295217708a(26) =632609378a(27) =1382640428a(28) =2974062096a(29) =6603081730