You got to be more specific about what you mean by a non-constant prime generating polynomial. If it is what I believe you mean, then this was noted in an earlier thread re Euler's function N^2 + N + 41. If you mean N takes only specific values such as "n = prime" or some sequence other than 1,2,3.... then there is no such proof. If you omit the constant 41 then of course each integer will be composit for n > 1, however, the basic proof for non existence of polynominals in general (no polynomial with integer coefficients will generate a prime for all n since if P(1) = a prime "p" then P(1 + t*p) will always be divisible by p) will work whether there is or is not a constant in the polynomial such as 41.
Edit:I believe that a variation of the proof will work for polynomials with rational coefficients also.