Number Theoretic Character
A number theoretic character, also called a Dirichlet character (because Dirichlet first introduced them in his famous proof that every arithmetic progression with relatively prime initial term and common difference contains infinitely many primes), modulo k is a complex function chi_k(n) for positive integer n such that
for all m,n, and
| chi_k(n)=0 |
(4)
|
if (k,n)!=1. chi_k can only assume values which are phi(k) roots of unity, where phi is the totient function.
Number theoretic characters are implemented in the Wolfram Language as DirichletCharacter [k, j, n], where k is the modulus and j is the index.
See also
Dirichlet L-Series, Multiplicative CharacterPortions of this entry contributed by Jonathan Sondow (author's link)
Explore with Wolfram|Alpha
More things to try:
Cite this as:
Sondow, Jonathan and Weisstein, Eric W. "Number Theoretic Character." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/NumberTheoreticCharacter.html