n = 10^60 + 7 = 1000000000000000000000000000000000000000000000000000000000007 Trial division < 100000 n - 1 = 2 * 7 * 107 * composite Pollard < 1000000 steps n - 1 = 2 * 7 * 107 * 1679641 * 8255453 * c_44 unable to factor c_44: primality proof FAILS. $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ 2ND EXAMPLE $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ n = 10^61 + 93 n - 1 = 10000000000000000000000000000000000000000000000000000000000093 trial divison < 100000 n - 1 = 2^2 * 3 * 2621 * 66037 * composite Pollard < 1000000 steps n - 1 = 2^2 * 3 * 2621 * 66037 * 3397567 * 1417086523103994077407747247360614547699381699 Miller-Rabin indicates that R = p_46 is prime and we do the Pocklington test: y = 2^((n-1)/R) = 7177493323391307598818294406496164465181399154046999462613725 mod n gcd(7177493323391307598818294406496164465181399154046999462613725 - 1, n) = 1 y^R = 1 mod n. So now we know: IF R IS PRIME, THEN n IS PRIME. ======================================== We now need to work with R = 1417086523103994077407747247360614547699381699 trial division < 100000 R - 1 = 2 * 59 * 919 * composite Pollard < 1000000 steps R - 1 = 2 * 59 * 919 * 385792526683 * 33872327408997649981423214143 Miller-Rabin indicates that R' = p_29 is prime and we do the Pocklington test: y = 2^((R-1)/R') = 949429449846548911690145068225670508279718398 mod R gcd(949429449846548911690145068225670508279718398 - 1, R) = 1 y^(R') = 1 mod R. So now we know: IF R' IS PRIME, THEN R IS PRIME. ========================================================================= We now need to work with R' = 33872327408997649981423214143 trial division < 100000 R' - 1 = 2 * 3 * 137 * 3701 * 11134074833788477626361 Miller-Rabin indicates that R'' = p_23 is prime and we do the Pocklington test: y = 2^((R'-1)/R'') = 1044414937576394936183462213 mod R' gcd(1044414937576394936183462213 - 1, R') = 1 y^(R'') = 1 mod R'. So now we know: IF R'' IS PRIME, THEN R' IS PRIME. ============================================================= We now need to work with R'' = 11134074833788477626361 trial division < 100000 R'' - 1 = 2^3 * 3^2 * 5 * composite Pollard < 1000000 steps R'' - 1 = 2^3 * 3^2 * 5 * 201389 * 153573361253159 Miller-Rabin indicates that R''' = p_15 is prime and we do the Pocklington test: y = 2^((R''-1)/R''') = 6823233954920652905481 mod R'' gcd(6823233954920652905481 - 1, R'') = 1 y^(R''') = 1 mod R''. So now we know: IF R''' IS PRIME, THEN R'' IS PRIME. ================================================================== We finally need to work with R''' = 153573361253159 trial division < 100000 R''' - 1 = 2 * 7 * 11 * 3547 * 281147341. All factors are prime and the last one q exceeds sqrt(R'''). We do the Pocklington test: y = 2^((R'''-1)/q) = 14965133413913 mod R''' gcd(14965133413913 - 1, R''') = 1 y^q = 1 mod R'''. So now we know that R''' IS PRIME. Backtracking shows that hence R'', hence R', hence R and hence n are primes. And now we are done: WE HAVE PROVED THAT n IS PRIME