Keeping Score

There's two schools of thought. The first is the pyramid theory, simply each generation the number doubles. If you stack the numbers up they resemble a pyramid. You can see the numbers listed in the chart below.

The problem is the numbers go up so fast somewhere around 30 generations you've suddenly got more great grandparents than there's been people on earth!

To deal with that the diamond theory was developed. Somewhere around the 10th generation the numbers start to get smaller. Historically families were a lot bigger and towns were a lot smaller. If you have a situation where your grandmothers were sisters the numbers in the previous generation are reduced by two.

In the case of this theory the numbers can't be estimated as they vary with the relationships. The only way to know for sure is to identify ALL the relatives. A major task indeed. The progress I've made is documented in the chart below.

Generation		How Many?	I've found...	Percentage
1	Self	1	1	100
2	Parents	2	2	100
3	Grandparents	4	4	100
4	Great Grandparents	8	8	100
5	Great X2	16	14	87.5
6	Great X3	32	12	37.5
7	Great X4	64	17	26.6
8	Great X5	128	22	17.2
9	Great X6	256	26	10.2
10	Great X7	512	34	6.6
11	Great X8	1024	40	3.9
12	Great X9	2048	39	1.9
13	Great X10	4096	44	1.07
14	Great X11	8192	33	0.4
15	Great X12	16384	19	0.16
16	Great X13	32768	19	0.06
17	Great X14	65536	14	0.02
18	Great X15	131072	6	0.005
19	Great X16	262144	3	0.0011
20	Great X17	524288	0	0