> 6 is not an amicable number because it's only amciable with itself. This > was not made clear anywhere,
Ermm, it says in the question that:
If d(a) = b and d(b) = a, where a (doesn't equal) b, then a and b are an
amicable pair and each of a and b are called amicable numbers.
Seems pretty clear that 6 is not an amicable number to me...
