a(0) = 0, a(1) = 1; a(2*n) = 9*a(n), a(2*n+1) = a(n) + a(n+1).

Terms

a(0) =0a(1) =1a(2) =9a(3) =10a(4) =81a(5) =19a(6) =90a(7) =91a(8) =729a(9) =100a(10) =171a(11) =109a(12) =810a(13) =181a(14) =819a(15) =820a(16) =6561a(17) =829a(18) =900a(19) =271a(20) =1539a(21) =280a(22) =981a(23) =919a(24) =7290a(25) =991a(26) =1629a(27) =1000a(28) =7371a(29) =1639