[0] Perl> for my $x ( 1 .. 4 ) {
    for my $y ( 1 .. 5 ) {
        print "Info for pair( $x, $y ) is stored at: ", $x*($x-1)/2 + $y;
    }
};;
Info for pair( 1, 1 ) is stored at:  1
Info for pair( 1, 2 ) is stored at:  2
Info for pair( 1, 3 ) is stored at:  3
Info for pair( 1, 4 ) is stored at:  4
Info for pair( 1, 5 ) is stored at:  5
Info for pair( 2, 1 ) is stored at:  2
Info for pair( 2, 2 ) is stored at:  3
Info for pair( 2, 3 ) is stored at:  4
Info for pair( 2, 4 ) is stored at:  5
Info for pair( 2, 5 ) is stored at:  6
Info for pair( 3, 1 ) is stored at:  4
Info for pair( 3, 2 ) is stored at:  5
Info for pair( 3, 3 ) is stored at:  6
Info for pair( 3, 4 ) is stored at:  7
Info for pair( 3, 5 ) is stored at:  8
Info for pair( 4, 1 ) is stored at:  7
Info for pair( 4, 2 ) is stored at:  8
Info for pair( 4, 3 ) is stored at:  9
Info for pair( 4, 4 ) is stored at:  10
Info for pair( 4, 5 ) is stored at:  11