Irregular triangular array read by rows. Let S_n be the set of labeled graphs G on [n] with 2-colored nodes where black nodes are only connected to white nodes and vice versa. Orient the edges in each such graph G from black to white. T(n,k) is the number of graphs in S_n containing exactly k descents, n>=0, 0<=k<=A002620(n).

A381058

Irregular triangular array read by rows. Let S_n be the set of labeled graphs G on [n] with 2-colored nodes where black nodes are only connected to white nodes and vice versa. Orient the edges in each such graph G from black to white. T(n,k) is the number of graphs in S_n containing exactly k descents, n>=0, 0<=k<=A002620(n).

Terms

    a(0) =1a(1) =2a(2) =5a(3) =1a(4) =16a(5) =8a(6) =2a(7) =67a(8) =56a(9) =30a(10) =8a(11) =1a(12) =374a(13) =436a(14) =358a(15) =188a(16) =68a(17) =16a(18) =2a(19) =2825a(20) =4143a(21) =4508a(22) =3460a(23) =2032a(24) =924a(25) =320a(26) =80a(27) =13a(28) =1a(29) =29212

External references