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In mathematics, summation is the addition of a sequence of numbers, called addends or summands; the result is their sum or total.Beside numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any type of mathematical objects on which an operation denoted "+" is defined.
Pairwise summation is the default summation algorithm in NumPy [9] and the Julia technical-computing language, [10] where in both cases it was found to have comparable speed to naive summation (thanks to the use of a large base case).
Summation describes the addition of arbitrarily many numbers, usually more than just two. It includes the idea of the sum of a single number, which is itself, and the empty sum, which is zero. [93] An infinite summation is a delicate procedure known as a series. [94] Counting a finite set is equivalent to summing 1 over the set.
A Taxicab number is the smallest positive number that can be expressed as a sum of two positive integer cubes in n distinct ways. The smallest taxicab number after Ta(1) = 1, is Ta(2) = 1729, [4] expressed as
The algorithm performs summation with two accumulators: sum holds the sum, and c accumulates the parts not assimilated into sum, to nudge the low-order part of sum the next time around. Thus the summation proceeds with "guard digits" in c , which is better than not having any, but is not as good as performing the calculations with double the ...
[a] Furthermore, it is the first in the family of absolute Euler pseudoprimes, a subset of Carmichael numbers. [7] 1729 is divisible by 19, the sum of its digits, making it a harshad number in base 10. [8] 1729 is the dimension of the Fourier transform on which the fastest known algorithm for multiplying two numbers is based. [9]
A square whose side length is a triangular number can be partitioned into squares and half-squares whose areas add to cubes. This shows that the square of the n th triangular number is equal to the sum of the first n cube numbers. Also, the square of the n th triangular number is the same as the sum of the cubes of the integers 1 to n.
If a number which is a sum of two squares is divisible by a prime which is a sum of two squares, then the quotient is a sum of two squares. (This is Euler's first Proposition). Indeed, suppose for example that a 2 + b 2 {\displaystyle a^{2}+b^{2}} is divisible by p 2 + q 2 {\displaystyle p^{2}+q^{2}} and that this latter is a prime.