Project Euler #6: difference between square of sum and sum of squares
for 1..100.
let euler6 n =
let sum = ref 0 in
let sum_sq = ref 0 in
for i = 1 to n do
sum := !sum + i;
sum_sq := !sum_sq + i * i
done;
!sum * !sum - !sum_sq
euler6 100 = 5050^2 - 338350 = 25502500 - 338350 = 25164150
102 baseline programs total.