Use the four numbers 1, 2, 3, and 4 to form a four-digit number, and at most one number is allowed to repeat twice. For example, 1234, 1233 and 2414 meet the conditions, but 1212, 3334 and 3333 do not meet the conditions. May I ask: How many four-digit numbers that meet the conditions can be formed in total?
用l、2、3、4这四个数字组成四位数，至多允许有1个数字重复两次．例如1234、1233和2414是满足条件的，而1212、3334和3333都不满足条件．请问：一共能组成多少个满足条件的四位数？
<gadget id="calculator">3 * 24</gadget>
<output>72</output>

<gadget id="calculator">2 * 24</gadget>
<output>48</output>

<gadget id="calculator">24 + 72 + 48 + 24</gadget>
<output>168</output>

<result>168</result>