static Boolean isPentagonal ( int N ) {
  double n = ( 1 + Math . sqrt ( 24 * N + 1 ) ) / 6 ;
  return ( n - ( int ) n ) == 0 ;
}

static Boolean isPentagonal ( int N ) { double n = ( 1 + Math . sqrt ( 24 * N + 1 ) ) / 6 ; return ( n - ( int ) n ) == 0 ; }
(method_declaration (modifiers) type: (type_identifier) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (local_variable_declaration type: (floating_point_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (parenthesized_expression (binary_expression left: (decimal_integer_literal) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (identifier)) right: (decimal_integer_literal)))))) right: (decimal_integer_literal)))) (return_statement (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (cast_expression type: (integral_type) value: (identifier)))) right: (decimal_integer_literal)))))