Emmm很不想写代码的感觉。

# CF392C Yet Another Number Sequence

## 题目描述

Everyone knows what the Fibonacci sequence is. This sequence can be defined by the recurrence relation:

$F_{1}=1,F_{2}=2,F_{i}=F_{i-1}+F_{i-2}$ We’ll define a new number sequence $A_{i}(k)$ by the formula:

$A_{i}(k)=F_{i}×i^{k} (i>=1).$ In this problem, your task is to calculate the following sum: $A_{1}(k)+A_{2}(k)+…+A_{n}(k)$ . The answer can be very large, so print it modulo 1000000007 $(10^{9}+7)$

## Solution

$F(2n,k) = \sum\limits_{i=1}^{n} + G^{n}_{1,1}\sum\limits_{i=1}^{n}G^{i}_{1,1}(i+n)^k$