The idempotent numbers are given by
 |
for integers 
, where 
is a partial Bell
polynomial and 
is a binomial coefficient. A table of the
first few is given below.
Idempotent Number
See also
Bell Polynomial, Lah Number, Partial Bell PolynomialExplore with Wolfram|Alpha
References
Comtet, L. Advanced Combinatorics: The Art of Finite and Infinite Expansions, rev. enl. ed. Dordrecht, Netherlands: Reidel, p. 91, 1974.Roman, S. The Umbral Calculus. New York: Academic Press, p. 85, 1984.Sloane, N. J. A. Sequences A000027/M0472, A001788/M4161, A036216, A040075, A050982, A050988, and A050989 in "The On-Line Encyclopedia of Integer Sequences."Referenced on Wolfram|Alpha
Idempotent NumberCite this as:
Weisstein, Eric W. "Idempotent Number." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/IdempotentNumber.html