static int summation ( int n ) {
  return n << ( n - 1 ) ;
}

static int summation ( int n ) { return n << ( n - 1 ) ; }
(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: (identifier) right: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal)))))))