Search results
Results from the WOW.Com Content Network
For example, the "primitive" friendly pair 6 and 28 gives rise to friendly pairs 6n and 28n for all n that are congruent to 1, 5, 11, 13, 17, 19, 23, 25, 29, 31, 37, or 41 modulo 42. [7] This shows that the natural density of the friendly numbers (if it exists) is positive.
Since the greatest prime factor of + = is 157, which is more than 28 twice, 28 is a Størmer number. [ 3 ] Twenty-eight is a harmonic divisor number , [ 4 ] a happy number , [ 5 ] the 7th triangular number , [ 6 ] a hexagonal number , [ 7 ] a Leyland number of the second kind [ 8 ] ( 2 6 − 6 2 {\displaystyle 2^{6}-6^{2}} ), and a centered ...
However, amicable numbers where the two members have different smallest prime factors do exist: there are seven such pairs known. [8] Also, every known pair shares at least one common prime factor. It is not known whether a pair of coprime amicable numbers exists, though if any does, the product of the two must be greater than 10 65.
The third largest prime factor is greater than 100, [28] and less than . [29] N has at least 101 prime factors and at least 10 distinct prime factors. [21] [30] If 3 does not divide N, then N has at least 12 distinct prime factors. [31] N is of the form
The multiplicity of a prime factor p of n is the largest exponent m for which p m ... A Ruth-Aaron pair is two consecutive numbers (x ... 18, 20, 22, 24, 26, 28, 30 ...
The smallest abundant number not divisible by 2 or by 3 is 5391411025 whose distinct prime factors are 5, 7, 11, 13, 17, 19, 23, ... (such as 6 and 28) ...
If the opposing team has the pair, then the bid value increases by 4 points. In some variations people also go for doubling or halving of the points depending on which person has the king/queen pair. In West Bengal, a variant of 28 is played where the lowest score is 16 and maximum is 28. In this variation, for a bid of 16-18 points, the ...
The notion of greatest common divisor can more generally be defined for elements of an arbitrary commutative ring, although in general there need not exist one for every pair of elements. [ 26 ] If R is a commutative ring, and a and b are in R , then an element d of R is called a common divisor of a and b if it divides both a and b (that is, if ...