00:01
We're asked to prove or disprove that the product of the first n primes plus 1 is prime for every positive integer n.
00:13
Well, to do this, let's consider different values of n.
00:21
So we have that the smallest prime numbers start with 2.
00:26
We have that if n is equal to 1, so i'll have two columns here, or three columns, n for the number of primes, then i have p1 multiplied through p n plus 1, and then i'll have prime, question mark.
00:51
Okay, so starting off with n equals 1, we have p1 is 2, so p1 plus 1 is 3, and we see that this is prime.
01:09
If n equals 2, we have the first two prime numbers are 2 and 3, so we have 2 times 3 plus 1.
01:17
6 plus 1 is 7.
01:19
This is prime.
01:26
Let's check if n equals 3.
01:32
So we have the first 3 prime numbers are 2, 3, and 5.
01:36
2 times 3 times 5 plus 1.
01:40
This is 30 plus 1, which is 31.
01:45
Excuse me.
01:47
And this is a prime number.
01:54
If n is equal to 4, the first 4 prime numbers are 2, 3, 5, and 7...