amicable numbers

Dickson (1913, 2005) defined an amicable triple to be a triple of three numbers (l, m, n) such that s(l) | = | m + n s(m) | = | l + n s(n) | = | l + m, where s(n) is the restricted divisor function. Dickson (1913, 2005) found eight sets of amicable triples with two equal numbers, and two sets with distinct numbers.

amicable pair | amicable quadruple