Nikaah & Marriage Issues

Lineage of the child born from couple having relations after divorce

Q: If a husband and wife divorce, do not marry anyone else, and after the waiting period (iddah) they mistakenly engage in a relationship that results in a child, then later repent and separate, can the man establish the child's lineage (nasab) through acknowledgment? What if the child's birth occurs 13 months after the divorce date?