Number of Dumont permutations of the first kind of length 2n avoiding the patterns 1423 and 4132.

A125187

Number of Dumont permutations of the first kind of length 2n avoiding the patterns 1423 and 4132.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =12a(4) =52a(5) =232a(6) =1049a(7) =4777a(8) =21845a(9) =100159a(10) =460023a(11) =2115350a(12) =9735205a(13) =44829766a(14) =206526972a(15) =951759621a(16) =4387156587a(17) =20226421380a(18) =93264500832a(19) =430091815527

External references