Number of alignments of n points with no singleton cycles.

A226226

Number of alignments of n points with no singleton cycles.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =2a(4) =12a(5) =64a(6) =470a(7) =3828a(8) =36456a(9) =387840a(10) =4603392a(11) =60061440a(12) =855664656a(13) =13207470912a(14) =219609303888

External references