use bigrat;

@s = qw(2, -4);
for my $n (2..99) {
    $s[$n]= 111.0 - 1130.0/$s[-1] + 3000.0/($s[-1]*$s[-2]);
}

for $n (3..8, 20, 30, 35, 50, 100) {
    ($nu,$de) = $s[$n-1] =~ m
    printf "n =%3d%18.15f\n", $n, $nu/$de;
}