On the Darboux integrability of a cubic CRN model in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msup><mml:mi mathvariant="double-struck">R</mml:mi><mml:mn>5</mml:mn></mml:msup></mml:math>
Chaos, solitons & fractals/Chaos, solitons and fractals