static long numbers ( int n ) {
  return ( long ) ( Math . pow ( 2 , n + 1 ) ) - 2 ;
}

static long numbers ( int n ) { return ( long ) ( Math . pow ( 2 , n + 1 ) ) - 2 ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (return_statement (binary_expression left: (cast_expression type: (integral_type) value: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (decimal_integer_literal) (binary_expression left: (identifier) right: (decimal_integer_literal)))))) right: (decimal_integer_literal)))))