Number of permutations on [n+2] with no circular 2-successions.

A284843

Number of permutations on [n+2] with no circular 2-successions.

Terms

    a(0) =3a(1) =12a(2) =55a(3) =318a(4) =2163a(5) =16952a(6) =150183a(7) =1483290a(8) =16153027a(9) =192234372a(10) =2481692343a(11) =34538108822a(12) =515428409715

External references