# python program to check if x is a perfect square
import math
# A utility function that returns true if x is perfect square
def isPerfectSquare(x):
s = int(math.sqrt(x))
return s*s == x
# Returns true if n is a Fibonacci Number, else false
def isFibonacci(n):
# n is Fibonacci if one of 5*n*n + 4 or 5*n*n - 4 or both is a perfect square
return isPerfectSquare(5*n*n + 4) or isPerfectSquare(5*n*n - 4)
# A utility function to test above functions
for i in range(1,11):
if (isFibonacci(i) == True):
print (i,"is a Fibonacci Number")
else:
print (i,"is a not Fibonacci Number ")
OUTPUT:
1 is a Fibonacci Number
2 is a Fibonacci Number
3 is a Fibonacci Number
4 is a not Fibonacci Number
5 is a Fibonacci Number
6 is a not Fibonacci Number
7 is a not Fibonacci Number
8 is a Fibonacci Number
9 is a not Fibonacci Number
10 is a not Fibonacci Number