Taylor series of a recursively defined function.

Terms

a(0) =1a(1) =1a(2) =2a(3) =-1a(4) =-2a(5) =1a(6) =5a(7) =-2a(8) =-16a(9) =16a(10) =32a(11) =-62a(12) =-3a(13) =11a(14) =57a(15) =806a(16) =-2700a(17) =-1186a(18) =19710a(19) =-28010a(20) =-56244a(21) =244815a(22) =-169425a(23) =-896555a(24) =2589156a(25) =-548641a(26) =-12351073a(27) =27233521a(28) =13281064a(29) =-170962713