Period of the continued fraction for sqrt(2^n-1).

Terms

a(0) =2a(1) =4a(2) =2a(3) =8a(4) =2a(5) =12a(6) =2a(7) =20a(8) =2a(9) =12a(10) =2a(11) =164a(12) =2a(13) =40a(14) =2a(15) =40a(16) =2a(17) =1208a(18) =2a(19) =660a(20) =2a(21) =1304a(22) =2a(23) =3056a(24) =2a(25) =2492a(26) =2a(27) =1080a(28) =2a(29) =13004