help with the closed form for a potential cons seq

[Joseph Biberstine]

Can you close Sum[2^(-k*(k + 9)/9), {k, 0, Infinity}]?

Or more usefully/generally, Sum[2^(p*k^2 + q*k + r), {k, 0, Infinity}] 
for p,q,r in the rationals and p negative?

I note the specific value is approx'ly 1.733126470890002...

- Joseph