using Mpir.NET;
using System;
using System.Collections.Generic;

namespace MersenneHint
{
    class Program
    {
        static void Main(string[] args)
        {
            var logFactor = Math.Log10(2);
            foreach (var p in GetPrimes(74000000, 75000000))
            {
                var digits = (int)Math.Floor(p * logFactor) + 1;
                var mpSec = mpz_t.Two.PowerMod(p, mpz_t.Ten.Power(digits - 19391387 + 1)) - 1;
                mpSec = mpSec.Divide(mpz_t.Ten.Power(digits - 19391387 + 1 - 7));
                var mpSecStr = mpSec.ToString();
                if (mpSecStr == "2718281")
                    Console.WriteLine(p);
            }
            Console.WriteLine("done");
            Console.ReadLine();
        }

        static IList<int> GetPrimes(int from, int to)
        {
            var primes = new List<int>();
            for (mpz_t i = new mpz_t(from).NextPrimeGMP(); i <= to; i = i.NextPrimeGMP())
            {
                primes.Add((int)i);
            }
            return primes;
        }
    }
}