On Thu, 26 Mar 2009, N. J. A. Sloane wrote: > Eric, doesn't A = [-1] also work? > > For then |A| = [1], per |A| = 1 = |det A|, so a(1) = 3 not 2 ? Sorry, Neil. I misread your "| det A |" as |A| == det A. That changes the counts to 3, 73, 12787, ... (Which also does not appear to be in OEIS). -E