请使用伪代码表达下面这个算式 1+1/2+1/3+1/4+1/5+1/7+1/8+…+1/20

使用伪代码表达下面这个算式：

sum = 1.0
for i in range(2, 21):
    if i == 6 or i == 9 or i == 10 or i == 12 or i == 14 or i == 15 or i == 16 or i == 18 or i == 20:
        continue
    if i % 2 == 0:
        sum = sum - 1.0 / i
    else:
        sum = sum + 1.0 / i
print(sum)