scipy.special.chdtrc

scipy.special.chdtrc(x1, x2[, out])

p=chdtrc(v,x) returns the area under the right hand tail (from x to infinity) of the Chi square probability density function with v degrees of freedom: 1/(2**(v/2) * gamma(v/2)) * integral(t**(v/2-1) * exp(-t/2), t=x..inf)