def test(n):
c = 0.0
for j in range(n):
for i in range(j + 1):
c = c + 1
return c
n = 10
c = test(n)
print(n, c, c / (n*n))
n = 20
c = test(n)
print(n, c, c / (n*n))
n = 50
c = test(n)
print(n, c, c / (n*n))
n = 100
c = test(n)
print(n, c, c / (n*n))
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