Every generation is being multiplied by 2.
5th: 16
6th: 32
7th: 64
8th: 128
9th: 256
10th: 512
11th: 1024
12th: 2048
13th: 4096
So the 13th generation gave 4,096 people.
15th: 8192
16th: 16384
17th: 32768
18th: 65536
19th: 131072
20th: 262144
21st: 524288
22nd: 1,048,576
23rd: 2,097,152
24th: 4,194,304
25th: 8,388,608
Then add the total of all generations to get the answer: 16,777,214
