O.g.f. A(x,y) satisfies: [x^n] exp( n * x*A(x,y) ) * (n + y - A(x,y)) = 0 for n > 0.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =2a(5) =2a(6) =15a(7) =30a(8) =18a(9) =6a(10) =232a(11) =492a(12) =400a(13) =144a(14) =24a(15) =5335a(16) =12450a(17) =11450a(18) =5240a(19) =1200a(20) =120a(21) =175416a(22) =439698a(23) =447744a(24) =237612a(25) =69672a(26) =10800a(27) =720a(28) =7847665a(29) =20851502