From 20 natural numbers from 1 to 20, find two numbers whose product is divisible by 12. How many pairs of such numbers are there?
从1至20的20个自然数中，找出两个数，使它们的乘积能被12整除，这样的数有多少对．
<gadget id="calculator">3 + 2 + 1</gadget>
<output>6</output>

<gadget id="calculator">5 + 3 + 2</gadget>
<output>10</output>

<gadget id="calculator">1 + 1 + 1</gadget>
<output>3</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<gadget id="calculator">1 + 6 + 10 + 10 + 3 + 8 + 8</gadget>
<output>46</output>

<result>46</result>