Search Results for ""

An infinite set, such as the real numbers, which is not countably infinite.

An aliquot sequence computed using the analog of the restricted divisor function s^*(n) in which only unitary divisors are included.

Sociable numbers computed using the analog of the restricted divisor function s^*(n) in which only unitary divisors are included.

A Turing machine which, by appropriate programming using a finite length of input tape, can act as any Turing machine whatsoever. In his seminal paper, Turing himself gave ...

An infinite sequence {a_i} of positive integers is called weakly independent if any relation sumepsilon_ia_i with epsilon_i=0 or +/-1 and epsilon_i=0, except finitely often, ...

Every nonempty set of positive integers contains a smallest member.

The 6-polyiamond illustrated above.

If three circles A, B, and C are taken in pairs, the external similarity points of the three pairs lie on a straight line. Similarly, the external similarity point of one ...

d is called an e-divisor (or exponential divisor) of a number n with prime factorization n=p_1^(a_1)p_2^(a_2)...p_r^(a_r) if d|n and d=p_1^(b_1)p_2^(b_2)...p_r^(b_r), where ...

A number n is called a k e-perfect number if sigma_e(n)=kn, where sigma_e(n) is the sum of the e-divisors of n.