When a natural number is divided by 8, the remainder is 1, and the resulting quotient is divided by 8, leaving a remainder of 1. Then, the quotient obtained for the second time is divided by 8, and the remainder is 7. Finally, the quotient obtained is a. We also know that the natural number is divided by 17, and the remainder is 4. The resulting quotient is divided by 17 and the remainder is 15. The final quotient obtained is twice a. Find this number.
一个自然数被8除余1，所得的商被8除也余1，再把第二次所得的商被8除后余7，最后得到一个商是a，又知这个自然数被17除余4，所得的商被17除余15，最后得到的商是a的2倍，求这个数．
<gadget id="calculator">8 * 249</gadget>
<output>1_992</output>

<gadget id="calculator">1_992 + 1</gadget>
<output>1_993</output>

<result>1_993</result>