Irregular triangle read by rows: T(n,k) is the number of essential graphs with n nodes and k (directed or undirected) edges (n >= 1, 0 <= k <= n*(n-1)/2).
A368569
Irregular triangle read by rows: T(n,k) is the number of essential graphs with n nodes and k (directed or undirected) edges (n >= 1, 0 <= k <= n*(n-1)/2).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =6a(6) =1a(7) =1a(8) =6a(9) =27a(10) =60a(11) =66a(12) =24a(13) =1a(14) =1a(15) =10a(16) =75a(17) =350a(18) =1120a(19) =2130a(20) =2595a(21) =1730a(22) =690a(23) =80a(24) =1a(25) =1a(26) =15a(27) =165a(28) =1235a(29) =6930
External references
- oeis: A368569