Sociable numbers are numbers that result in a periodic aliquot sequence, where an aliquot sequence is the sequence of numbers obtained by repeatedly applying the restricted divisor function s(n) = σ(n) - n to n and σ(n) is the usual divisor function. If the period of the aliquot cycle is 1, the number is called a perfect number. If the period is 2, the two numbers are called an amicable pair. In general, if the period is t>=3, the number is called sociable of order t. For example, 1264460 is a sociable number of order four since its aliquot sequence is 1264460, 1547860, 1727636, 1305184, 1264460, ....
We guarantee you’ll find the right tutor, or we’ll cover the first hour of your lesson.