题解 | 尼科彻斯定理

n = int(input())
k = n*(n-1)/2
value = int(2*k+1)
output = str(value)
i = 1
while i < n:
    value = int(2*(k+i)+1)
    output = output + "+" + str(value)
    i = i+1
print(output)