#yuki797

mod=10**9+7
n=int(raw_input())
a=map(int,raw_input().split())
res=0
t=1
for i in xrange(n):
 res+=t*a[i]
 res%=mod
 t*=n-i-1
 t%=mod
 t*=pow(i+1,mod-2,mod)
 t%=mod
print res