Dual q-Krawtchouk polynomials

The polynomials are given in terms of basic hypergeometric functions by

${\displaystyle K_{n}(\lambda (x);c,N|q)={}_{3}\phi _{2}(q^{-n},q^{-x},cq^{x-N};q^{-N},0|q;q),\quad n=0,1,2,...,N,}$

where ${\displaystyle \lambda (x)=q^{-x}+cq^{x-N}.}$