Search results
Results from the WOW.Com Content Network
Quasi-sociable numbers or reduced sociable numbers are numbers whose aliquot sums minus one form a cyclic sequence that begins and ends with the same number. They are generalizations of the concepts of betrothed numbers and quasiperfect numbers. The first quasi-sociable sequences, or quasi-sociable chains, were discovered by Mitchell Dickerman ...
where n > 1 is an integer and p, q, r are prime numbers, then 2 n × p × q and 2 n × r are a pair of amicable numbers. This formula gives the pairs (220, 284) for n = 2, (17296, 18416) for n = 4, and (9363584, 9437056) for n = 7, but no other such pairs are known. Numbers of the form 3 × 2 n − 1 are known as Thabit numbers.
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.
Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more
The most significant difference between the NGSQ and the Register Systems is in the method of numbering for children who are not carried forward into future generations: The NGSQ System assigns a number to every child, whether or not that child is known to have progeny, and the Register System does not. Other differences between the two systems ...
The pair had been betrothed since Mary was five and Francis was three. Mary had originally been betrothed when she was six months old to the future Edward VI of England, whom she was supposed to marry at the age of ten. Lucrezia de' Medici (aged 12) was married to Alfonso II d'Este, Duke of Modena (aged 24), in 1558. As Alfonso was fighting in ...
The principal wedding sponsors (also termed "godparents," "special sponsors," "primary sponsors," "counselors," or "witnesses"), [7] are often chosen by the betrothed, sometimes on advice of their families. Multiple pairs of godparents are customary, with six godmothers (ninang) and six godfathers (ninong)