Rossmo's formula

#!/usr/bin/env python3
#Rossmo's formula
import math

crimes=[(5,4), (6,3), (5,3), (7,3)]
phi=5
f, g= 2, 2
b=3
a=0
for j in range(10):
    for i in range(10):
       for crime in crimes:
           equation= 0
           distance= (i-crime[0])+(j-crime[1])
           equation+= (phi/math.pow(distance, f))
           numerator= (1-phi)*math.pow(b, 8-f)
           denominator= math.pow(2*b-distance, g)
           equation+= (numerator/denominator)
           a+=equation
       print(i,',', j,': ', a)
       a=0