Successive prime differences: Difference between revisions
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:#https://www.primepuzzles.net/puzzles/puzz_011.htm
:#https://matheplanet.de/matheplanet/nuke/html/viewtopic.php?topic=232720&start=0
=={{header|C sharp}}==
<lang csharp>using System;
using System.Collections.Generic;
using static System.Linq.Enumerable;
public static class SuccessivePrimeDifferences
{
public static void Main() {
var primes = GeneratePrimes(1_000_000).ToList();
foreach (var d in new[] {
new [] { 2 },
new [] { 1 },
new [] { 2, 2 },
new [] { 2, 4 },
new [] { 4, 2 },
new [] { 6, 4, 2 },
}) {
IEnumerable<int> first = null, last = null;
int count = 0;
foreach (var grp in FindDifferenceGroups(d)) {
if (first == null) first = grp;
last = grp;
count++;
}
Console.WriteLine($"{$"({string.Join(", ", first)})"}, {$"({string.Join(", ", last)})"}, {count}");
}
IEnumerable<IEnumerable<int>> FindDifferenceGroups(int[] diffs) {
for (int pi = diffs.Length; pi < primes.Count; pi++) {
if (Range(0, diffs.Length).All(di => primes[pi-diffs.Length+di+1] - primes[pi-diffs.Length+di] == diffs[di])) {
yield return Range(pi - diffs.Length, diffs.Length + 1).Select(i => primes[i]);
}
}
}
}
}</lang>
{{out}}
<pre>
(3, 5), (999959, 999961), 8169
(2, 3), (2, 3), 1
(3, 5, 7), (3, 5, 7), 1
(5, 7, 11), (999431, 999433, 999437), 1393
(7, 11, 13), (997807, 997811, 997813), 1444
(31, 37, 41, 43), (997141, 997147, 997151, 997153), 306
</pre>
=={{header|Factor}}==
{{works with|Factor|0.99}}
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