Marc LeBrun <mlb at fxpt.com> wrote: : From the OEIS we learn, among many other things, that 2005 is... [...] : 6 4^5 + 5 4^4 + 4 4^3 + 3 4^2 + 2 4^1 + 1 4^0 [A059045] That should be 3^5, 3^4 etc. Hugo