343572domain: NAppears in sequencesNumber of simple unlabeled n-node graphs with 2 center nodes.at n=9A052438Number of permutations of 1..n containing the relative rank sequence { 136245 } at any spacing.at n=4A159103Triangle read by rows: T(n,k) is the number of simple connected graphs on n nodes with k center nodes.at n=46A294525