a(0) = 1, a(n) = sum of binary digits of all prior terms, expressed in binary.

Terms

a(0) =1a(1) =1a(2) =10a(3) =11a(4) =101a(5) =111a(6) =1010a(7) =1100a(8) =1110a(9) =10001a(10) =10011a(11) =10110a(12) =11001a(13) =11100a(14) =11111a(15) =100100a(16) =100110a(17) =101001a(18) =101100a(19) =101111a(20) =110100a(21) =110111a(22) =111100a(23) =1000000a(24) =1000001a(25) =1000011a(26) =1000110a(27) =1001001a(28) =1001100a(29) =1001111