How many 16th cousins might I have?

Question

it occurred to me to wonder when one of them posed the question to me:

 May I ask please if you would include my name on to your list of relations.?

Comments

A very random number.

All of the 15g-grandchildren of your 882 known 15g-grandparents.

Some of those might have an awful lot, which makes averages meaningless.

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Even the number of 16th cousins (plus alleged 16th cousins) within WikiTree is likely to be mindbogglingly large. It would include me (in the alleged cousin category), since WikiTree maps us as 14th cousins, and Relationship Finder says "5 common ancestors were found between Sir William and Ellen within 15 generations."

Answer 1

One could easily have multiple million 16th cousins. 

I found this:

A study by AncestryDNA, based on British birth rates, census data, parliamentary research briefings[3] and other sources for the last 200 years, produced the following statistics on the number of cousins that the average British person would be expected to have.[4]

Relationship	Number of cousins
First cousins	5
Second cousins	28
Third cousins	175
Fourth cousins	1,570
Fifth cousins	17,300
Sixth cousins	174,000

 

"Cousin Statistics." Autosomal DNA - ISOGG Wiki. Accessed July 06, 2018. https://isogg.org/wiki/Cousin_statistics.