Negabinary Keith numbers.

Terms

a(0) =2a(1) =3a(2) =4a(3) =7a(4) =9a(5) =13a(6) =16a(7) =36a(8) =55a(9) =64a(10) =162a(11) =256a(12) =458a(13) =1024a(14) =1829a(15) =4096a(16) =7316a(17) =15119a(18) =16384a(19) =18970a(20) =37702a(21) =37723a(22) =45171a(23) =60476a(24) =65536a(25) =84506a(26) =262144a(27) =277263a(28) =1048576a(29) =1109052