A sum which includes both the Jacobi triple product and the *q*-binomial theorem as special
cases. Ramanujan's sum is

where the notation denotes *q*-series.
For ,
this becomes the *q*-binomial theorem.

A sum which includes both the Jacobi triple product and the *q*-binomial theorem as special
cases. Ramanujan's sum is

where the notation denotes *q*-series.
For ,
this becomes the *q*-binomial theorem.

Weisstein, Eric W. "Ramanujan Psi Sum."
From *MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/RamanujanPsiSum.html