Search results
Results from the WOW.Com Content Network
The first few pairs of betrothed numbers (sequence A005276 in the OEIS) are: (48, 75), ... Handbook of Number Theory I. Dordrecht: Springer-Verlag. p. 113.
Although all amicable pairs up to 10,000 are even pairs, the proportion of odd amicable pairs increases steadily towards higher numbers, and presumably there are more of them than of the even amicable pairs (A360054 in OEIS). Gaussian integer amicable pairs exist, [14] [15] e.g. s(8008+3960i) = 4232-8280i and s(4232-8280i) = 8008+3960i. [16]
The period of the sequence, or order of the set of sociable numbers, is the number of numbers in this cycle. If the period of the sequence is 1, the number is a sociable number of order 1, or a perfect number—for example, the proper divisors of 6 are 1, 2, and 3, whose sum is again 6. A pair of amicable numbers is a set of sociable numbers of ...
A number that is not part of any friendly pair is called solitary. The abundancy index of n is the rational number σ(n) / n, in which σ denotes the sum of divisors function. A number n is a friendly number if there exists m ≠ n such that σ(m) / m = σ(n) / n. Abundancy is not the same as abundance, which is defined as σ(n) − 2n.
The aliquot sequence starting with a positive integer k can be defined formally in terms of the sum-of-divisors function σ 1 or the aliquot sum function s in the following way: [1] = = = > = = = If the s n-1 = 0 condition is added, then the terms after 0 are all 0, and all aliquot sequences would be infinite, and we can conjecture that all aliquot sequences are convergent, the limit of these ...
A natural number is a sociable Kaprekar number if it is a periodic point for ,, where , = for a positive integer (where , is the th iterate of ,), and forms a cycle of period . A Kaprekar number is a sociable Kaprekar number with k = 1 {\displaystyle k=1} , and a amicable Kaprekar number is a sociable Kaprekar number with k = 2 {\displaystyle k ...
A number of Floyd's Young and the Restless costars shared their well-wishes after the newly engaged couple jointly posted one of their engagement photos on Instagram.
According to Guy, Erdős has asked whether there are infinitely many pairs of consecutive powerful numbers such as (23 3, 2 3 3 2 13 2) in which neither number in the pair is a square. Walker (1976) showed that there are indeed infinitely many such pairs by showing that 3 3 c 2 + 1 = 7 3 d 2 has infinitely many solutions.