Cluster size for wireless networks

ClusterSize.py

#!/usr/bin/env python

list = []

def n(i, j):
    return (i ** 2) + (j ** 2) - (i * j)

for x in range(1, 11):
    for y in range(x + 1):
        _n = n(x, y)
        try:
            list.index(_n)
        except:
            list.append(_n)

list.sort()
print(list)