Four positive integers a, b, c, d are all less than 1000, and form a four-array (a, b, c, d), if a+4, b-4, c*4, d/4 are also positive integers, And they are all equal, so how many such different four-arrays are there?
四个正整数a、b、c、d都小于1000，并且组成一个四数组(a、b、c、d)，如果a+4、b-4、c*4、d/4也是正整数，而且都相等，那么这样的不同四数组共有多少个．
<gadget id="calculator">62 - 1</gadget>
<output>61</output>

<result>61</result>