Denominator of the n-th convergent to Sum_{k>=0} 1/2^(2^k).

Terms

a(0) =1a(1) =1a(2) =5a(3) =11a(4) =49a(5) =207a(6) =1291a(7) =5371a(8) =12033a(9) =53503a(10) =333051a(11) =719605a(12) =3211471a(13) =19988431a(14) =83165195a(15) =352649211a(16) =788463617a(17) =3506503679a(18) =21827485691a(19) =47161475061a(20) =210473385935a(21) =889055018801