Best Rx Fibonacci

Fibonacci.java

import java.util.ArrayList;
import java.util.Arrays;

import io.reactivex.Observable;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.BiFunction;
import io.reactivex.functions.Consumer;
import io.reactivex.functions.Function;

public class Fibonacci {
    public static Observable<Integer> fibonacci(int index) {
        return Observable.range(1, 1).
                repeat(index).
                scan(new ArrayList<>(Arrays.asList(0, 1)), new BiFunction<ArrayList<Integer>, Integer, ArrayList<Integer>>() {
                            @Override
                            public ArrayList<Integer> apply(ArrayList<Integer> list, Integer integer) {
                                list.add(list.get(list.size() - 2) + list.get(list.size() - 1));
                                list.remove(0);
                                return list;
                            }
                        }
                ).map(new Function<ArrayList<Integer>, Integer>() {
            @Override
            public Integer apply(ArrayList<Integer> list) {
                return list.get(list.size() - 1);
            }
        });
    }

    public static void main(String[] args) {
        Observable<Integer> fibonacci = fibonacci(7);
        Disposable disposable = fibonacci.subscribe(new Consumer<Integer>() {
            @Override
            public void accept(Integer integer) {
                System.out.println(integer);
            }
        });
    }
}