Multiplying Ancestors

Starting with my two parents, I have:

• 4 grandparents
• 8 great grandparents
• 16 second great grandparents
• 32 third great grandparents
• 64 fourth great grandparents
• 128 fifth great grandparents
• 256 sixth great grandparents
• 512 seventh great grandparents
• 1024 eight great grandparents
• 2048 ninth great grandparents
• 4096 tenth great grandparents
• 8192 eleventh great grandparents

(Copied from Find-A-Grave member Mona Hura)

Intriguingly, the multiplication will somewhere stop and funnel back to two first parents, Adam and Eve.