1127388domain: NAppears in sequencesTriangle read by rows: T(n,k) is the number of labeled graphs with vertex set [n] that are reachable in k (but no fewer) steps from a given graph on [n], where a step consists of choosing a subset S of [n] and replacing the subgraph induced by S with its complement, 0 <= k <= n-1.at n=25A370609