a(n) = denominator(n / (4^n - 2^n)) for n > 0 and a(0) = 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =56a(4) =60a(5) =992a(6) =672a(7) =16256a(8) =8160a(9) =261632a(10) =523776a(11) =4192256a(12) =1397760a(13) =67100672a(14) =134209536a(15) =1073709056a(16) =268431360a(17) =17179738112a(18) =3817734144a(19) =274877382656a(20) =54975528960a(21) =628292059136