NJAS: I can't reconstruct this. Possibly an erroneous version of A003050 or A048259 - njas. Check the Author line: Author(s): njas Erm, Neil, have you seen a psychartrist lately? Jon Perry perry at globalnet.co.uk http://www.users.globalnet.co.uk/~perry/maths/ http://www.users.globalnet.co.uk/~perry/DIVMenu/ BrainBench MVP for HTML and JavaScript http://www.brainbench.com