Task: Fibonacci n-step number sequences
C#: using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Fibonacci
{
    class Program
    {
        static void Main(string[] args)
        {
            PrintNumberSequence("Fibonacci", GetNnacciNumbers(2, 10));
            PrintNumberSequence("Lucas", GetLucasNumbers(10));
            PrintNumberSequence("Tribonacci", GetNnacciNumbers(3, 10));
            PrintNumberSequence("Tetranacci", GetNnacciNumbers(4, 10));
            Console.ReadKey();
        }

        private static IList<ulong> GetLucasNumbers(int length)
        {
            IList<ulong> seedSequence = new List<ulong>() { 2, 1 };
            return GetFibLikeSequence(seedSequence, length);
        }

        private static IList<ulong> GetNnacciNumbers(int seedLength, int length)
        {
            return GetFibLikeSequence(GetNacciSeed(seedLength), length);
        }

        private static IList<ulong> GetNacciSeed(int seedLength)
        {
            IList<ulong> seedSquence = new List<ulong>() { 1 };

            for (uint i = 0; i < seedLength - 1; i++)
            {
                seedSquence.Add((ulong)Math.Pow(2, i));
            }

            return seedSquence;
        }

        private static IList<ulong> GetFibLikeSequence(IList<ulong> seedSequence, int length)
        {
            IList<ulong> sequence = new List<ulong>();

            int count = seedSequence.Count();

            if (length <= count)
            {
                sequence = seedSequence.Take((int)length).ToList();
            }
            else
            {
                sequence = seedSequence;

                for (int i = count; i < length; i++)
                {
                    ulong num = 0;

                    for (int j = 0; j < count; j++)
                    {
                        num += sequence[sequence.Count - 1 - j];
                    }

                    sequence.Add(num);
                }
            }

            return sequence;
        }

        private static void PrintNumberSequence(string Title, IList<ulong> numbersequence)
        {
            StringBuilder output = new StringBuilder(Title).Append("   ");

            foreach (long item in numbersequence)
            {
                output.AppendFormat("{0}, ", item);
            }

            Console.WriteLine(output.ToString());
        }
    }
}

Java: class Fibonacci
{
  public static int[] lucas(int n, int numRequested)
  {
    if (n < 2)
      throw new IllegalArgumentException("Fibonacci value must be at least 2");
    return fibonacci((n == 2) ? new int[] { 2, 1 } : lucas(n - 1, n), numRequested);
  }
  
  public static int[] fibonacci(int n, int numRequested)
  {
    if (n < 2)
      throw new IllegalArgumentException("Fibonacci value must be at least 2");
    return fibonacci((n == 2) ? new int[] { 1, 1 } : fibonacci(n - 1, n), numRequested);
  }
  
  public static int[] fibonacci(int[] startingValues, int numRequested)
  {
    int[] output = new int[numRequested];
    int n = startingValues.length;
    System.arraycopy(startingValues, 0, output, 0, n);
    for (int i = n; i < numRequested; i++)
      for (int j = 1; j <= n; j++)
        output[i] += output[i - j];
    return output;
  }
  
  public static void main(String[] args)
  {
    for (int n = 2; n <= 10; n++)
    {
      System.out.print("nacci(" + n + "):");
      for (int value : fibonacci(n, 15))
        System.out.print(" " + value);
      System.out.println();
    }
    for (int n = 2; n <= 10; n++)
    {
      System.out.print("lucas(" + n + "):");
      for (int value : lucas(n, 15))
        System.out.print(" " + value);
      System.out.println();
    }
  }
}