@see primality test
Level 1:
Check if all integers between 2 and x – 1 give non-zero remainder when divided into x.
Level 2:
Check if all integers between 2 and x/2 give non-zero remainder when divided into x.
Level 3:
Check if all integers between 2 and sqrt(x) give non-zero remainder when divided into x.
Level 4:
Check if number 2 and all odd integers between 3 and sqrt(x) give non-zero remainder when divided into x.
Level 5:
Check if number 2 and number 3 and some integers between 5 and sqrt(x) give non-zero remainder when divided into x. Only check numbers via the following pattern:
- check if 5 and 7 give non-zero remainder when divided into x
- check if 5+6 and 7+6 give non-zero remainder when divided into x
- check if 5+2*6 and 7+2*6 give non-zero remainder when divided into x
- check if 5+3*6 and 7+3*6 give non-zero remainder when divided into x
- etc
Level 6:
Check if number 2 and number 3 and some integers between 5 and sqrt(x) give non-zero remainder when divided into x. Only check numbers via the following pattern:
- check if 5 and 7 give non-zero remainder when divided into x
- check if 5+6 and 7+6 give non-zero remainder when divided into x
- check if 5+2*6 and 7+2*6 give non-zero remainder when divided into x
- check if 5+3*6 and 7+3*6 give non-zero remainder when divided into x
- etc
but skip integers that end with 5.
Level 7:
Use Elliptic curve primality tests or other unconditional probabilistic methods like Goldwasser–Kilian test or Miller–Rabin test
