Data update

Task/Ormiston-triples/FreeBASIC/ormiston-triples.basic

@@ -0,0 +1,53 @@
+Function GetSig(Byval N As Uinteger) As Uinteger      'Return signature of N
+    'A "signature" is the count of each digit in N packed into a 32-bit word
+    Dim As Uinteger Sig = 0
+    Do While N > 0
+        Sig += 1 Shl (N Mod 10)
+        N \= 10
+    Loop
+    Return Sig
+End Function
+
+Dim As Uinteger limite = 1e9
+Dim Shared As Boolean Sieve(limite)
+
+Sub MakeSieve(Size As Uinteger)     'Make prime number sieve
+    Dim As Uinteger Prime, i, K
+    Size \= 2                       'ignore even numbers
+    For i = 0 To Size               'set Sieve flags all true
+        Sieve(i) = True
+    Next
+    For i = 0 To Size
+        If Sieve(i) Then            'found a prime, which is equal to
+            Prime = i * 2 + 3       ' twice the index + 3
+            K = i + Prime           'first multiple to strike off
+            While K <= Size         'strike off all multiples
+                Sieve(K) = False
+                K += Prime
+            Wend
+        End If
+    Next
+End Sub
+
+MakeSieve(limite)
+Print "Smallest members of first 25 Ormiston triples:"
+Dim As Uinteger Cnt = 0, N0 = 0, N1 = 0, Sig0 = 0, Sig1 = 0, N = 3, Sig
+Dim As Double t0 = Timer
+Do
+    If Sieve(N \ 2 - 1) Then        ' is prime
+        Sig = GetSig(N)
+        If Sig = Sig0 Andalso Sig = Sig1 Then
+            Cnt += 1
+            If Cnt <= 25 Then
+                Print Using "#,###,###,###"; N0;
+                If Cnt Mod 5 = 0 Then Print
+            End If
+        End If
+        Sig0 = Sig1: Sig1 = Sig
+        N0 = N1: N1 = N
+    End If
+    If N >= limite Then Print Cnt; " Ormiston triples before one billion." : Exit Do
+    N += 2
+Loop
+
+Sleep