In number theory, a pernicious number is a positive integer such that the Hamming weight of its binary representation is prime, that is, there is a prime number of 1s when it is written as a binary number.[1]
^Deza, Elena (2021), Mersenne Numbers And Fermat Numbers, World Scientific, p. 263, ISBN 978-9811230332
In number theory, a perniciousnumber is a positive integer such that the Hamming weight of its binary representation is prime, that is, there is a prime...
Pernicious anemia is a disease where not enough red blood cells are produced due to a deficiency of vitamin B12. Those affected often have a gradual onset...
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that...
the number 1 differently than larger numbers, sometimes even not as a number at all. Euclid, for example, defined a unit first and then a number as a...
In mathematics, the Fibonacci sequence is a sequence in which each number is the sum of the two preceding ones. Numbers that are part of the Fibonacci...
triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples...
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has...
A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a triangular base and three sides, called a tetrahedron...
In number theory, 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...
In mathematics, a square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with...
In mathematics, a harshad number (or Niven number) in a given number base is an integer that is divisible by the sum of its digits when written in that...
A cyclic number is an integer for which cyclic permutations of the digits are successive integer multiples of the number. The most widely known is the...
2,5,15,52,203,877,4140,\dots } (sequence A000110 in the OEIS). The Bell number B n {\displaystyle B_{n}} counts the different ways to partition a set that...
In number theory, a Thabit number, Thâbit ibn Qurra number, or 321 number is an integer of the form 3 ⋅ 2 n − 1 {\displaystyle 3\cdot 2^{n}-1} for a non-negative...
A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16461) that remains the same when its digits are...
coprime. Consequently, a prime number divides at most one prime-exponent Mersenne number. That is, the set of pernicious Mersenne numbers is pairwise coprime...
recreational mathematics, a vampire number (or true vampire number) is a composite natural number with an even number of digits, that can be factored into...
perfect number (also called multiperfect number or pluperfect number) is a generalization of a perfect number. For a given natural number k, a number n is...
In number theory, an n-smooth (or n-friable) number is an integer whose prime factors are all less than or equal to n. For example, a 7-smooth number is...
In number theory, a congruent number is a positive integer that is the area of a right triangle with three rational number sides. A more general definition...
not reject foreign assistance altogether, although they regarded it as pernicious. While China supplied them with substantial food aid, this was not publicly...
In number theory, a happy number is a number which eventually reaches 1 when replaced by the sum of the square of each digit. For instance, 13 is a happy...
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The...
composite number is a positive integer that has more divisors than any smaller positive integer. A related concept is that of a largely composite number, a positive...
was discovered as a result of pernicious anemia, an autoimmune disorder in which the blood has a lower than normal number of red blood cells, due to a...
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