# Method Gmp.mpz()->bin()

Method bin

  `Gmp.mpz bin(int k)`

Description

  Return the binomial coefficient `n` over k, where `n` is the value of this mpz object. Negative values of `n` are supported using the identity

  (-n)->bin(k) == (-1)->pow(k) * (n+k-1)->bin(k)

(See Knuth volume 1, section 1.2.6 part G.)

Throws

  The k value can't be arbitrarily large. An error is thrown if it's too large.

Note

  This function is currently (Pike 7.8) not available with old releases of the gmp libraries.