> n;
p = 2;
b = 0;
i = 1;
{ n - i ?
     k = 1;
     x = 2 + b;
     y = x;
     { k - 2*5 ?
       y = x/(2*y)+y/2;
       k = k + 1; }
     b = y;
   t = 2/b;
   p = p*t;
   i = i + 1;
   < i; < B; < p; < N;
} $