- a
semiperfect number or
pseudoperfect number is a
natural number n that is
equal to the sum of all or some of its
proper divisors. A
semiperfect number...
- In mathematics, a
semiperfect magic cube is a
magic cube that is not a
perfect magic cube, i.e., a
magic cube for
which the
cross section diagonals do...
- 304 is a
primitive semiperfect number meaning that it is a
semiperfect number that is not
divisible by any
other semiperfect number. 304 is an untouchable...
- 9.
Three of
these divisors (3, 6 and 9) add up to 18,
hence 18 is a
semiperfect number.
Eighteen is the
first inverted square-prime of the form p·q2...
- of Euler's
totient function φ(x) over the
first sixteen integers. a
semiperfect number,
since adding up some
subsets of its
divisors (e.g., 1, 4, 5,...
-
semiperfect cube of
order 64 and a
perfect cube of
order 256. It also
reports that he
discovered the only two
known tetramagic cubes, a
semiperfect cube...
- a
hexagonal number. a
Icositrigonal number a semi-meandric number. a
semiperfect number,
being a
multiple of a
perfect number. an Erdős–Woods number,...
- 100 can be
expressed as a sum of some of its divisors,
making it a
semiperfect number. The
geometric mean of its nine
divisors is 10. 100 is the sum...
- side but not the other.
Perfect rings were
introduced in B****'s book. A
semiperfect ring is a ring over
which every finitely generated left
module has a...
-
aliquot sum of 42,
which is the
second sphenic number. It is also: A
semiperfect number,
since adding some
subsets of its
divisors (e.g., 5, 10 and 15)...
