Any pair of integers a,b such that the factors of b add up to a and the factors of a add up to b.

220,284 represents such a pair, since the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110, of which the sum is 284; and the proper divisors of 284 are 1, 2, 4, 71, and 142, of which the sum is 220.

sionnach commented on the word amicable numbers

Any pair of integers a,b such that the factors of b add up to a and the factors of a add up to b.

220,284 represents such a pair, since the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110, of which the sum is 284; and the proper divisors of 284 are 1, 2, 4, 71, and 142, of which the sum is 220.

Mathematical Aphrodisiac

November 17, 2007