Java utility to compute n-step fibonacci suite

Fibo.java

package com.croutard;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;

public class Fibo
{
    private static final BigDecimal ZERO = new BigDecimal("0");
    private static final BigDecimal ONE = new BigDecimal("1");
    private static final BigDecimal TWO = new BigDecimal("2");
    private static final List<BigDecimal> SEED = Arrays.asList(ZERO, ONE);
    private static final Map<Integer, List<BigDecimal>> SEED_CACHE = new HashMap<>();
    private static final Integer ORDER_2 = 2;

    private static Queue<BigDecimal> fibo(Queue<BigDecimal> values, int n)
    {
        for (int i = 0; i < n; i++) {
            BigDecimal next_value = sum(values);
            values.poll();
            values.add(next_value);
        }

        return values;
    }

    private static List<BigDecimal> fibo(List<BigDecimal> values, int n, int k)
    {
        for (int i = 0; i < n; i++) {
            values.add(sum(values.subList(values.size() - k, values.size())));
        }
        return values;
    }

    private static List<BigDecimal> seed(int k)
    {
        List<BigDecimal> seed = new ArrayList<>();
        for (int i = 0; i < k; i++) {

            seed.add(fibo(k - 1, i));
        }
        return seed;
    }

    private static BigDecimal fibo(int k, int n)
    {
        if (k == ORDER_2) {
            //System.out.println("n: " + n);
            List<BigDecimal> values = fibo(new ArrayList<>(SEED), n, ORDER_2);
            return values.get(values.size() - 1);
        }

        List<BigDecimal> seed;
        if (!SEED_CACHE.containsKey(k)) {
            SEED_CACHE.put(k, seed(k));
        }
        seed = SEED_CACHE.get(k);
        return fibo(new LinkedList<>(seed), n).peek();
    }

    private static BigDecimal sum(Collection<BigDecimal> values)
    {
        return values.parallelStream().reduce(BigDecimal::add).get();
    }

    public static void main(String[] args)
    {
        int n = 10;
        int k = 3;

        System.out.println("fibo_k(n+2):" + fibo(k, n + 2));
    }
}