Expansion of Sum_{k>=0} x^(4^k) / (1 - 4*x^(4^k)).

Terms

a(0) =1a(1) =4a(2) =16a(3) =65a(4) =256a(5) =1024a(6) =4096a(7) =16388a(8) =65536a(9) =262144a(10) =1048576a(11) =4194320a(12) =16777216a(13) =67108864a(14) =268435456a(15) =1073741889a(16) =4294967296a(17) =17179869184a(18) =68719476736a(19) =274877907200