Problem 31
Coin Sums
In the United Kingdom the currency is made up of pound (£) and pence (p). There are eight coins in general circulation:
1p, 2p, 5p, 10p, 20p, 50p, £1 (100p), and £2 (200p).
It is possible to make £2 in the following way:
1×£1 + 1×50p + 2×20p + 1×5p + 1×2p + 3×1p
How many different ways can £2 be made using any number of coins?
硬币求和
英国的货币单位分为英镑（£）和便士（p）。目前流通的硬币一共有八种面值：
1p, 2p, 5p, 10p, 20p, 50p, £1 (100p) 和 £2 (200p).
想要凑出£2，其中一种做法是：
1×£1 + 1×50p + 2×20p + 1×5p + 1×2p + 3×1p
不限制硬币数量，凑出£2有多少种不同的做法？