human
Pell Number | Calculate nth pell number.
Driver function"
How can the above be solved in Python?
assistant
#Here is code to pell Number and the other steps required.
 def pell ( n ) :
	if ( n <= 2 ) :
		return n
	return ( 2 * pell ( n - 1 ) + pell ( n - 2 ) )
n = 4 ;
print ( pell ( n ) )