Let $[x]_{q}=\frac{1-q^x}{1-q}$ and $\binom{x}{n}_{q}$ denote a $q$-binomial coefficient.
Let $A_n(x,q)$ be the $n\times n $ matrix with entries $$q^\binom{i-j}{2}\binom{i+j+x}{i-j+1}_{q},$$ $0 \le i,j \le n-1,$ and $n+1\le m \le 2n-1.$
Computer experiments suggest that $ A_n(-m,q) v_{n,m}=0$ if $v_{n,m}$ is the vector with entries $$q^{(\lfloor{m/2}\rfloor-j) (\lfloor{m/2}\rfloor+5-3j)/2}\frac{[m]_q}{[m-j]_q}\binom{m-j}{j}_{q}$$ for even $m$ and $$q^{(\lfloor{m/2}\rfloor-j) (\lfloor{m/2}\rfloor+7-3j)/2}\frac{[m]_q}{[m-j]_q}\binom{m-j}{j}_{q}$$ for odd $m.$
Any idea how to prove this?
For $q=1$ one can use Rothe’s formula, but I could not find a $q$-analogue which applies to the general case.