power23 [ ] will store pairwise product of elements of power2 and power3 that are <= r
var power23 = [ ] ; for ( var x = 0 ; x < power2 . length ; x ++ ) { for ( var y = 0 ; y < power3 . length ; y ++ ) { var mul = power2 [ x ] * power3 [ y ] ; if ( mul == 1 ) continue ;