Number of signed weighted Euler trees with total weight n (associated to even switching classes of matrices of order 2n).

A110886

Number of signed weighted Euler trees with total weight n (associated to even switching classes of matrices of order 2n).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =8a(4) =27a(5) =104a(6) =436a(7) =1930a(8) =8871a(9) =41916a(10) =202300a(11) =992942a(12) =4940912a(13) =24867870a(14) =126371426a(15) =647494746a(16) =3341341155a(17) =17350565376a(18) =90593056624a(19) =475333630402

External references