Number of forests of rooted trees of nonempty sets with n points. (Each node is a set of 1 or more points.)

A052855

Number of forests of rooted trees of nonempty sets with n points. (Each node is a set of 1 or more points.)

Terms

    a(0) =1a(1) =1a(2) =3a(3) =8a(4) =24a(5) =71a(6) =224a(7) =710a(8) =2318a(9) =7659a(10) =25703a(11) =87153a(12) =298574a(13) =1031104a(14) =3587263a(15) =12558652a(16) =44214807a(17) =156438309a(18) =555973965a(19) =1983817178a(20) =7104313970a(21) =25525304569a(22) =91986529421a(23) =332408847422

External references