Finds the initial term and common difference and prints the resulting array .
if ( n == 3 ) : NEW_LINE INDENT common_difference = arr [ 2 ] - arr [ 1 ] NEW_LINE initial_term = arr [ 1 ] - common_difference NEW_LINE DEDENT elif ( ( arr [ 1 ] - arr [ 0 ] ) == arr [ 2 ] - arr [ 1 ] ) : NEW_LINE