4244481domain: NAppears in sequencesNumber of colored labeled n-node graphs with 2 interchangeable colors.at n=7A000684Array read by antidiagonals: T(n,k) = n! * Sum_{s} 2^(Sum_{i=1..k-1} s(i)*s(i+1))/(Product_{i=1..k} s(i)!) where the sum is over all nonnegative compositions s of n into k parts.at n=62A361950