Numbers that when raised to the fourth power and written backwards give squares.

Terms

a(0) =0a(1) =1a(2) =10a(3) =11a(4) =100a(5) =101a(6) =110a(7) =1000a(8) =1001a(9) =1010a(10) =1100a(11) =10000a(12) =10001a(13) =10010a(14) =10100a(15) =11000a(16) =100000a(17) =100001a(18) =100010a(19) =100100a(20) =101000a(21) =110000a(22) =1000000a(23) =1000001a(24) =1000010a(25) =1000100a(26) =1001000a(27) =1010000a(28) =1100000a(29) =10000000