Low Pass Current to Voltage Amplifier with 2 Op-Amps
It's too late for math.

The second opamp is non-inverting with gain 1+R3/R2 = 2.66666 ; I labeled &quot;op1&quot; the output of the first opamp, so V(out) = 2.666*V(op1). Since the input of the first amp is a virtual ground, current through R1 (the resistor on top) is v(out)/R1 = v(op1)*2.6666/R1, so I remove the second opamp, connect R1 to the output of the first, and divide its value by 2.666 to keep the same current. The simulator agrees.
Since we have two resistors in parallel, I remove one and replace the other with their parallel resistance, giving the same result.
The result is a standard integrator. It will behave a bit differently at HF when the opamp poles stick out, though.