G.f. A(x) satisfies: A(x) = 1 - x^3 * A(x/(1 - x)) / (1 - x).

Terms

a(0) =1a(1) =0a(2) =0a(3) =-1a(4) =-1a(5) =-1a(6) =0a(7) =4a(8) =15a(9) =40a(10) =86a(11) =134a(12) =16a(13) =-1060a(14) =-6119a(15) =-25187a(16) =-86678a(17) =-250846a(18) =-537819a(19) =-175233a(20) =6998009a(21) =55632942a(22) =310923272a(23) =1465146781a(24) =6011047682a(25) =20719304348a(26) =49356093300a(27) =-36579100806