sub   xx2{ int(   2**(   2**( rand() * logN( $_[0],   2 ) ) ) ) }
sub  xx10{ int(  10**(  10**( rand() * logN( $_[0],  10 ) ) ) ) }
sub  xx20{ int(  20**(  20**( rand() * logN( $_[0],  20 ) ) ) ) }
sub xx100{ int( 100**( 100**( rand() * logN( $_[0], 100 ) ) ) ) }