rename statics/euler and sync b93 code with main repo

www/statics/euler/Euler_Problem-040_explanation.md

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+This one is really great - I came up with an O(log n) algorithm (crazy fast) for determining the n-th digit.  
+First I tested it in LinqPad, so here the C# code for the algorithm:
+
+```csharp
+public int digitAt(int pos) {
+    int digitcount = 1;
+    int digitvalue = 1;
+    
+    // Get DigitCount of current number
+    while(pos > digitvalue * 9 * digitcount) {
+        pos -= digitvalue * 9 * digitcount;
+        digitcount++;
+        digitvalue *= 10;
+    }
+    
+    // current number and digit-position in number
+    int value = digitvalue + (pos - 1)/digitcount;
+    int digit = digitcount - (pos - 1)%digitcount - 1;
+    
+    return getInternalDigit(value, digit);
+}
+
+public int getInternalDigit(int value, int digit) {
+    return (value / (int)Math.Pow(10, digit)) % 10;
+}
+```