recursive factorial function

factorial.js

function factorial( n ) {
  if (n > 1) {
    return factorial(n-1) * n;
  } else {
    return 1;
  }
}

console.log( factorial( 1 )  1      );
console.log( factorial( 3 ), 6      );
console.log( factorial( 5 ), 120    );
console.log( factorial( 6 ), 720    );
console.log( factorial( 9 ), 362880 );
console.log( factorial( 15 ), 1307674368000 );
console.log( factorial( 20 ), 2432902008176640000 );