c-sharp-math-2025101.cs

           var sp = new Stopwatch();

           sp.Start();

           Parallel.For(1, 10, a =>
           {
               Parallel.For(1, 10, b =>
               {
                   Parallel.For(1, 10, c =>
                   {
                       Parallel.For(1, 10, d =>
                       {
                           long left = 25870 + a;
                           int right = (int)Math.Pow(2, b) * c * d * d * 11; // 2^b * c * d² * 11

                           if (left == right)
                           {
                               Console.WriteLine($"a={a}, b={b}, c={c}, d={d}, sum={left}");
                           }
                       });
                   });
               });
           });
           Console.WriteLine(sp.Elapsed);
           
           //a=2, b=3, c=6, d=7, sum=25872
           //a=2, b=4, c=3, d=7, sum=25872
           //00:00:00.0154183