Marco Beri wrote: > Bravo il mio amico, eh? :-) Chi e'? Lo conosco... A me piace barare: % time python erat_matrix.py 10000000 (array([ 2, 3, 5, ..., 9999971, 9999973, 9999991]),) python erat_matrix.py 10000000 0.61s user 0.12s system 38% cpu 1.930 total -- . ..: -enrico-