Bessel numbers: the number of nonoverlapping partitions of an n-set into equivalence classes.

A006789

Bessel numbers: the number of nonoverlapping partitions of an n-set into equivalence classes.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =43a(6) =143a(7) =509a(8) =1922a(9) =7651a(10) =31965a(11) =139685a(12) =636712a(13) =3020203a(14) =14878176a(15) =75982829a(16) =401654560a(17) =2194564531a(18) =12377765239a(19) =71980880885a(20) =431114329728

External references