Vincenzo said: > For the controll: %F A074506 a(n)=7*a(n-1)-12*a(n-2)+6 with a(1)=3, a(2)=8 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jul 16 2010] I'm not quite sure what " For the controll" means, but this is wrong, the offset is 0, so a(0) = 3 (a(1)=3 is wrong) Neil