In the second post, there is the signature of Qsum.
That makes them two. The addresses in the first post are 18. So, 15 signatures left. What we now need is the other signatures except for Satoshi's key. Then we would be able to calculate it.
No. We only have signatures from - 1s1wZLBTjFZJi8DrN1kogV9ZxRZxwvKQJ - and - 1C1gQwDk2sxEaYVuMjBiuCAYaNw1JE2N3s. Maybe they (Satoshi) want us to calculate it?
Yes. That's what Satoshi does on Wednesdays. He's trying to see if some strangers can steal his identity. 