I think they still use the Elliptic curves ECF or Quadratic Sieves.
Take a look here:
https://www.alpertron.com.ar/ECM.HTM
]]>This is because the sum of any group of numbers all separated by +1, I.e. 3,4,5,6,7 will be an odd composite with factors of the middle number and the length.
Examples:
2+3+4+5+6+7+8
Middle number=5
Length=7
Therefore=5*7=35
14+15+16+17+18+19+20
Middle number=17
Length=7
Therefore=7*17=119
116+117+118
Middle number=117
Length=3
Therefore=3*117=351
Therefore I would have thought we would be able to compute prime numbers faster by minusing the potential prime, p, off triangular numbers <p to see if they equal another triangular number. If they don't p is prime. This surely must be faster than seeing if p is factorable by all possible factors......................?
Does anyone know how people are using computers to test if very, very, VERY large numbers are prime?
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