Number of permutations of [n] such that for each cycle c the smallest integer interval containing all elements of c has at most four elements.

A276838

Number of permutations of [n] such that for each cycle c the smallest integer interval containing all elements of c has at most four elements.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =60a(6) =150a(7) =399a(8) =1145a(9) =3132a(10) =8420a(11) =22716a(12) =62128a(13) =169536a(14) =460885a(15) =1251777a(16) =3406238a(17) =9272354a(18) =25229036a(19) =68622196a(20) =186682470a(21) =507925571a(22) =1381929921a(23) =3759616968a(24) =10228269080a(25) =27827267544a(26) =75707898304a(27) =205971928848a(28) =560368255081

External references