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using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.IO;

namespace Infoboard
{
	class MainClass
	{
		static List<BigInteger> Collatz(int start, int factor, string filename) {
			//zum nachgucken, ob schon gefunden - HashSet ist da schneller
			HashSet<BigInteger> found = new HashSet<BigInteger> ();
			//exakte Reihenfolge des Auftretens
			List<BigInteger> sequence = new List<BigInteger> ();
			BigInteger next = new BigInteger (start);
			using (StreamWriter sw = new StreamWriter(filename)) {
				while (!found.Contains(next)) {
					found.Add (next);
					sequence.Add (next);
					if (next.IsEven)
						next /= 2;
					else
						next = factor * next + 1;
					if (sequence.Count % 1000 == 0) //alle 1000 Werte einen ausgeben
						sw.WriteLine (sequence.Count + " " + BigInteger.Log10 (sequence.Last ()));
					if (sequence.Count > 500000) {
						Console.WriteLine (sequence.Max ().ToString ().Length);
						return new List<BigInteger> { sequence.Max() };
					}
				}
				sequence.Add (next);
			}
			return sequence;
		}

		static void Main(string[] args) {
			for (int i = 1; i < 8; i++) {
				Console.WriteLine (string.Join (" ", Collatz (i, 5, "output" + i + ".txt")));
			}
		}
	}
}

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using System;
using System.Collections.Generic;
using System.Linq;

namespace Infoboard
{
	class MainClass
	{
		static void Main(string[] args) {
			int max = (int)1e6;
			long[] collatz = new long[max + 1];
			for (int f = 3; f < 10000; f += 2) {
				for (long i = 1; i <= max; i++) {
					if (i % 2 == 0)
						collatz [i] = i / 2;
					else
						collatz [i] = f * i + 1;
				}
				List<List<long>> loops = new List<List<long>> ();
				for (int start = 1; start <= max; start++) {
					if (collatz [start] == 0)
						continue;
					List<long> seq = new List<long> ();
					long current = start;
					while (current <= max && collatz[current] != 0) {
						seq.Add (current);
						long tmp = collatz [current];
						collatz [current] = 0;
						current = tmp;
					}
					if (current == start)
						loops.Add (seq);
				}
				if (loops.Count > 0)
					Console.WriteLine (f + ": " + string.Join ("  :  ", loops.Select (loop => string.Join (", ", loop))));
			}
		}
	}
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.IO;

namespace Infoboard
{
	class MainClass
	{
		static List<BigInteger> Collatz(int start, int factor, int maxLoop, string filename) {
			//zum nachgucken, ob schon gefunden - HashSet ist da schneller
			HashSet<BigInteger> found = new HashSet<BigInteger> ();
			//exakte Reihenfolge des Auftretens
			List<BigInteger> sequence = new List<BigInteger> ();
			BigInteger next = new BigInteger (start);
			while (!found.Contains (next) && found.Count < maxLoop) {
				found.Add (next);
				sequence.Add (next);
				if (next.IsEven)
					next /= 2;
				else
					next = factor * next + 1;
				if (next < sequence [0])
					break;
			}
			sequence.Add (next);
			if (sequence[0] == next) {
				Console.WriteLine ("f = " + factor + ": " + string.Join (", ", sequence));
				if (filename != null) {
					using (StreamWriter sw = new StreamWriter (filename, true))
						sw.WriteLine ("f = " + factor + ": " + string.Join (", ", sequence));
				}
			}
			return sequence;
		}

		static void Main(string[] args) {
			int maxLoop = 10000; //maximale Länge eines Zyklus
			string outputFile = null; //hier Dateinamen für Ausgabe eintragen, z.B. "/home/eulerschezahl/Dokumente/output.txt" (Linux) oder @"C:\Users\eulerschezahl\output.txt" (Windows)
			for (int factor = 3; factor < 1000; factor += 2) { //Collatz Abbildungsvorschrift
				for (int start = 1; start <= 500; start++) { //nur an diesen Stellen mit Suche beginnen
					Collatz (start, factor, maxLoop, outputFile);	
				}
			}
		}
	}
}

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using System;
using System.Linq;
using System.Collections.Generic;

class Collatz
{
	static int Steps(long n) {
		int result = 0;
		while (n > 1) {
			if (n % 2 == 0)
				n /= 2;
			else {
				n = 3 * n + 1;
				result++;
			}
		}
		return result;
	}

	static void Main() {
		List<int> zerfall = new List<int> ();
		for (int i = 3; i < 1024; i += 2) {
			int tmp = Steps (i);
			while (zerfall.Count <= tmp)
				zerfall.Add (0);
			zerfall [tmp]++;
		}
		for (int i = 1; i < zerfall.Count; i++) {
			Console.WriteLine (i + ": " + zerfall [i]);
		}
	}
}