Mersenne primes: Difference between revisions
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m (added a Prime Numbers category and a note about the largest Mersenne Prime know as of December, 2018.) |
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sidef mersenne.sf 12.47s user 0.02s system 99% cpu 12.495 total |
sidef mersenne.sf 12.47s user 0.02s system 99% cpu 12.495 total |
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</pre> |
</pre> |
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=={{header|Visual Basic .NET}}== |
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{{trans|C#}} |
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<lang vbnet>Imports System.Numerics |
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Module Module1 |
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Function Sqrt(x As BigInteger) As BigInteger |
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If x < 0 Then |
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Throw New ArgumentException("Negative argument.") |
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End If |
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If x < 2 Then |
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Return x |
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End If |
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Dim y = x / 2 |
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While y > (x / y) |
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y = ((x / y) + y) / 2 |
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End While |
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Return y |
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End Function |
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Function IsPrime(bi As BigInteger) As Boolean |
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If bi < 2 Then |
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Return False |
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End If |
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If bi Mod 2 = 0 Then |
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Return bi = 2 |
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End If |
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If bi Mod 3 = 0 Then |
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Return bi = 3 |
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End If |
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If bi Mod 5 = 0 Then |
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Return bi = 5 |
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End If |
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If bi Mod 7 = 0 Then |
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Return bi = 7 |
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End If |
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If bi Mod 11 = 0 Then |
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Return bi = 11 |
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End If |
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If bi Mod 13 = 0 Then |
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Return bi = 13 |
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End If |
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If bi Mod 17 = 0 Then |
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Return bi = 17 |
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End If |
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If bi Mod 19 = 0 Then |
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Return bi = 19 |
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End If |
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Dim limit = Sqrt(bi) |
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Dim test As BigInteger = 23 |
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While test < limit |
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If bi Mod test = 0 Then |
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Return False |
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End If |
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test += 2 |
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If bi Mod test = 0 Then |
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Return False |
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End If |
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test += 4 |
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End While |
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Return True |
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End Function |
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Sub Main() |
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Const MAX = 9 |
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Dim pow = 2 |
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Dim count = 0 |
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While True |
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If IsPrime(pow) Then |
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Dim p = BigInteger.Pow(2, pow) - 1 |
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If IsPrime(p) Then |
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Console.WriteLine("2 ^ {0} - 1", pow) |
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count += 1 |
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If count >= MAX Then |
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Exit While |
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End If |
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End If |
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End If |
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pow += 1 |
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End While |
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End Sub |
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End Module</lang> |
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{{out}} |
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<pre>2 ^ 2 - 1 |
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2 ^ 3 - 1 |
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2 ^ 5 - 1 |
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2 ^ 7 - 1 |
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2 ^ 13 - 1 |
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2 ^ 17 - 1 |
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2 ^ 19 - 1 |
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2 ^ 31 - 1 |
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2 ^ 61 - 1</pre> |
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=={{header|Wren}}== |
=={{header|Wren}}== |
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