Double and reverse digits.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =61a(5) =221a(6) =244a(7) =884a(8) =8671a(9) =24371a(10) =24784a(11) =86594a(12) =881371a(13) =2472671a(14) =2435494a(15) =8890784a(16) =86518771a(17) =245730371a(18) =247064194a(19) =883821494a(20) =8892467671a(21) =24353948771a(22) =24579870784a(23) =86514795194a(24) =883095920371