Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with join of length k.

A318392

Regular triangle where T(n,k) is the number of pairs of set partitions of {1,...,n} with join of length k.

Terms

    a(0) =1a(1) =3a(2) =1a(3) =15a(4) =9a(5) =1a(6) =119a(7) =87a(8) =18a(9) =1a(10) =1343a(11) =1045a(12) =285a(13) =30a(14) =1a(15) =19905a(16) =15663a(17) =4890a(18) =705a(19) =45a(20) =1a(21) =369113a(22) =286419a(23) =95613a(24) =16450a(25) =1470a(26) =63a(27) =1a(28) =8285261a(29) =6248679

External references