Reverse and add (in base 4).

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =10a(5) =20a(6) =25a(7) =50a(8) =85a(9) =170a(10) =340a(11) =425a(12) =850a(13) =1385a(14) =3070a(15) =6140a(16) =10225a(17) =15335a(18) =29410a(19) =65135a(20) =129070a(21) =317675a(22) =1280860a(23) =2163725a(24) =3999775a(25) =7999550a(26) =20321515a(27) =81946460a(28) =138412045a(29) =255852575