A Pair of numbers and such that
See also Amicable Pair, Divisor Function, Quasiamicable Pair
References
Beck, W. E. and Najar, R. M. ``More Reduced Amicable Pairs.'' Fib. Quart. 15, 331-332, 1977.
Guy, R. K. Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, p. 59, 1994.