G.f. (1-x)/(2*sqrt(5*x^2 + 2*x + 1)) - 1/2.

Terms

a(0) =-1a(1) =0a(2) =3a(3) =-5a(4) =-3a(5) =26a(6) =-35a(7) =-48a(8) =245a(9) =-248a(10) =-639a(11) =2355a(12) =-1573a(13) =-7890a(14) =22555a(15) =-6685a(16) =-93075a(17) =212280a(18) =27625a(19) =-1061415a(20) =1938855a(21) =1276550a(22) =-11763465a(23) =16906450a(24) =23324507a(25) =-126971664a(26) =136840575a(27) =343314517a(28) =-1334857995a(29) =965192298