The Lucas-Lehmer test that M74207281 is prime requires 74M steps. Writing down the remainders of the X2-2 (mod P) iteration, at 22M digits each, would take 1.6Q characters. If we included the arithmetic to confirm each squaring step, another factor of 22M, we have 35 sextillion characters. We could reduce this a lot with Karatsuba or FFT multiplication, but we're still at 1.6Q * log2(74M) ~= 40 quadrillion characters. Is this any different from the 200T problem? Rich -------------- Quoting Eric Angelini <Eric.Angelini@kntv.be>:
http://www.nature.com/news/two-hundred-terabyte-maths-proof-is-largest-ever-...
à+ É. Catapulté de mon aPhone
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