Data commit

Task/Successive-prime-differences/Python/successive-prime-differences.py

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+# https://docs.sympy.org/latest/index.html
+from sympy import Sieve
+
+def nsuccprimes(count, mx):
+    "return tuple of <count> successive primes <= mx (generator)"
+    sieve = Sieve()
+    sieve.extend(mx)
+    primes = sieve._list
+    return zip(*(primes[n:] for n in range(count)))
+
+def check_value_diffs(diffs, values):
+    "Differences between successive values given by successive items in diffs?"
+    return all(v[1] - v[0] == d
+               for d, v in zip(diffs, zip(values, values[1:])))
+
+def successive_primes(offsets=(2, ), primes_max=1_000_000):
+    return (sp for sp in nsuccprimes(len(offsets) + 1, primes_max)
+            if check_value_diffs(offsets, sp))
+
+if __name__ == '__main__':
+    for offsets, mx in [((2,),      1_000_000),
+                        ((1,),      1_000_000),
+                        ((2, 2),    1_000_000),
+                        ((2, 4),    1_000_000),
+                        ((4, 2),    1_000_000),
+                        ((6, 4, 2), 1_000_000),
+                       ]:
+        print(f"## SETS OF {len(offsets)+1} SUCCESSIVE PRIMES <={mx:_} WITH "
+              f"SUCCESSIVE DIFFERENCES OF {str(list(offsets))[1:-1]}")
+        for count, last in enumerate(successive_primes(offsets, mx), 1):
+            if count == 1:
+                first = last
+        print("  First group:", str(first)[1:-1])
+        print("   Last group:", str(last)[1:-1])
+        print("        Count:", count)