Expansion of -(2*x)/(1-sqrt(1-(2*(1-sqrt(1-4*x^2)))/x)).

Terms

a(0) =-1a(1) =1a(2) =2a(3) =2a(4) =7a(5) =18a(6) =61a(7) =198a(8) =694a(9) =2446a(10) =8873a(11) =32556a(12) =121243a(13) =455986a(14) =1731459a(15) =6625258a(16) =25527571a(17) =98947914a(18) =385587017a(19) =1509702496a(20) =5936181673a(21) =23430706276a(22) =92805006308a(23) =368747893980