def main1(n,a):
  dp=[0]*n
  mod=10**9+7
  dp[0]=1
  d={}
  base=0
  c=int(n**0.5)+1
  ary=[{} for i in range(n)]
  for i in range(n):

    # マスiに到達するケースを加算
    if ary[i]:
      for k,v in ary[i].items():
        dp[i]=(dp[i]+v)%mod
        if i+k<n:
          if k in ary[i+k]:
            ary[i+k][k]+=v
          else:
            ary[i+k][k]=v
    dp[i]+=base
    dp[i]%=mod
    if i==n-1:break
    k=a[i]
    if k==1:
      base+=dp[i]
      base%=mod
    elif k<c:
      dp[i+1]+=dp[i]
      dp[i+1]%=mod
      if i+k<n:
        if k in ary[i+k]:
          ary[i+k][k]+=dp[i]
          ary[i+k][k]%=mod
        else:
          ary[i+k][k]=dp[i]
    else:
      dp[i+1]+=dp[i]
      dp[i+1]%=mod
      ii=i+k
      while ii<n:
        dp[ii]+=dp[i]
        dp[ii]%=mod
        ii+=k
  return dp[-1]

if __name__=='__main__':
  n=int(input())
  a=list(map(int,input().split()))
  ret1=main1(n,a)
  print(ret1)