Number of signed permutations of length n invariant under the reverse complement and avoiding (-2, -1), (-2, 1), (2, -1).

A193776

Number of signed permutations of length n invariant under the reverse complement and avoiding (-2, -1), (-2, 1), (2, -1).

Terms

    a(0) =1a(1) =2a(2) =3a(3) =5a(4) =12a(5) =17a(6) =65a(7) =80a(8) =473a(9) =527a(10) =4444a(11) =4679a(12) =51391a(13) =52628a(14) =703659a(15) =711449a(16) =11098896a(17) =11156477a(18) =197809793a(19) =198299024a(20) =3927270089a(21) =3931960343a(22) =85908742132a(23) =85958728847

External references