589822domain: NAppears in sequencesa(n) = 9*4^n - 2.at n=7A153465a(n) = 9*2^n - 2.at n=16A176449Least positive squarefree integer k such that Q(sqrt(k)) has a class number greater than that of any previous integer.at n=22A279908Number of acyclic edge covers of the complete bipartite graph K_{n,2}.at n=15A328890