a(n) = -4*binomial(2*n-5, n-4)/n for n > 0 and a(0) = 1.

Terms

a(0) =1a(1) =-4a(2) =2a(3) =0a(4) =-1a(5) =-4a(6) =-14a(7) =-48a(8) =-165a(9) =-572a(10) =-2002a(11) =-7072a(12) =-25194a(13) =-90440a(14) =-326876a(15) =-1188640a(16) =-4345965a(17) =-15967980a(18) =-58929450a(19) =-218349120a(20) =-811985790a(21) =-3029594040a(22) =-11338026180a(23) =-42550029600a(24) =-160094486370a(25) =-603784920024