G.f. A(x) satisfies: 1 = Product_{n>=1} (1 - x^n) * (1 - x^(n+1)/A(x)) * (1 - x^(n-2)*A(x)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =9a(5) =22a(6) =52a(7) =146a(8) =377a(9) =1036a(10) =2810a(11) =8014a(12) =22790a(13) =66100a(14) =191541a(15) =562926a(16) =1660975a(17) =4944766a(18) =14767136a(19) =44357952a(20) =133698623a(21) =404810569a(22) =1229434572a(23) =3746595869a(24) =11447723074a(25) =35075829156a(26) =107724187826a(27) =331605018200