Python math.exp function Syntax

D[case] = (Dref[case]*((50/ t)^ m )) * ( math.exp((20/6)*((1/295) – (1/Temp)))

It seems to be extra parentheses

Try

D[case] = (Dref[case]*((50/ t)^ m )) * math.exp((20/6)*((1/295) – (1/Temp)))