M=10**9+7
def extended_euclid_algorithm(a,b)
  d0,x0,y0,d1,x1,y1=a,1,0,b,0,1
  until d1==0
    q=d0/d1
    d0,x0,y0,d1,x1,y1=d1,x1,y1,d0-q*d1,x0-q*x1,y0-q*y1
  end
  [d0,x0,y0]
end

def inverse(a)
  d,x,y=extended_euclid_algorithm(a,M)
  x%M
end

n=gets.to_i-1
a=gets.split.map(&:to_i)
ans=0
comb=1
a.each_with_index{|v,i|
  ans=(ans+comb*v)%M
  comb=(comb*(n-i)*inverse(i+1))%M
}

puts ans%M