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Task/Bernoulli-numbers/Visual-Basic-.NET/bernoulli-numbers.vb

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+' Bernoulli numbers - vb.net - 06/03/2017
+Imports System.Numerics 'BigInteger
+
+Module Bernoulli_numbers
+
+    Function gcd_BigInt(ByVal x As BigInteger, ByVal y As BigInteger) As BigInteger
+        Dim y2 As BigInteger
+        x = BigInteger.Abs(x)
+        Do
+            y2 = BigInteger.Remainder(x, y)
+            x = y
+            y = y2
+        Loop Until y = 0
+        Return x
+    End Function 'gcd_BigInt
+
+    Sub bernoul_BigInt(n As Integer, ByRef bnum As BigInteger, ByRef bden As BigInteger)
+        Dim j, m As Integer
+        Dim f As BigInteger
+        Dim anum(), aden() As BigInteger
+        ReDim anum(n + 1), aden(n + 1)
+        For m = 0 To n
+            anum(m + 1) = 1
+            aden(m + 1) = m + 1
+            For j = m To 1 Step -1
+                anum(j) = j * (aden(j + 1) * anum(j) - aden(j) * anum(j + 1))
+                aden(j) = aden(j) * aden(j + 1)
+                f = gcd_BigInt(BigInteger.Abs(anum(j)), BigInteger.Abs(aden(j)))
+                If f <> 1 Then
+                    anum(j) = anum(j) / f
+                    aden(j) = aden(j) / f
+                End If
+            Next
+        Next
+        bnum = anum(1) : bden = aden(1)
+    End Sub 'bernoul_BigInt
+
+    Sub bernoulli_BigInt()
+        Dim i As Integer
+        Dim bnum, bden As BigInteger
+        bnum = 0 : bden = 0
+        For i = 0 To 60
+            bernoul_BigInt(i, bnum, bden)
+            If bnum <> 0 Then
+                Console.WriteLine("B(" & i & ")=" & bnum.ToString("D") & "/" & bden.ToString("D"))
+            End If
+        Next i
+    End Sub 'bernoulli_BigInt
+
+End Module 'Bernoulli_numbers