On Jan 15, 2008 4:31 AM, Maximilian Hasler <maximilian.hasler at gmail.com> wrote: > (08:48) gp > sum(i=1,#a6,1/i) I think you meant 1/a6[i] not 1/i. btw, it is simpler to verify modulo large random prime: E.g.: ? p=nextprime(random(10^10)) %3 = 6101502223 ? sum(i=1,#a6,Mod(1/a6[i],p)) %4 = Mod(3354880885, 6101502223) So, it cannot be equal 6. Regards, Max