#include<iostream>
#include<vector>
#include<cassert>
#include<set>
#ifdef _GLIBCXX_DEBUG
#include<sstream>
#define cin cin_
namespace std{
std::stringstream cin(R"(
4
4 1 1 5
)");
};
#endif
int constexpr MOD=1000000007;
int main(){
std::ios::sync_with_stdio(0);std::cin.tie(0);
int n;std::cin>>n;
std::vector<int> a(n);
for(int& x:a){
std::cin>>x;
--x;
}
std::set<int> s; // zeckendorf repr
std::vector<int> stk;
for(int x:a){
// add F[x] to s
assert(stk.empty());
stk.push_back(x);
#define x _DONT_USE_THIS
do{ // TODO: reduce (nnum*log) to (nnum+log)
int y=stk.back();stk.pop_back();
auto it=s.lower_bound(y-1);
if(it==s.end()||*it>y+1){
s.insert(y);
}else if(*it<y){
assert(*it==y-1);
s.erase(it);
stk.push_back(y+1);
}else if(*it==y){
s.erase(it);
stk.push_back(y+1);
if(y==0){ // assume F[-1] == 1 and F[-2] == 0
assert(y-2 == -2);
continue;
}else
stk.push_back(std::max(0,y-2));
}else{
assert(*it==y+1);
s.erase(it);
stk.push_back(y+2);
}
}while(!stk.empty());
// for(int y:s)std::cout<<y<<' ';
// std::cout<<'\n';
int const n=s.size();
std::vector<int> f0(n),f1(n);
assert(n>0);
int s0=*s.begin();
f0[0]=s0/2u; // [i] = number of repr of [0..i] -> F{x | x<s[i]}
f1[0]=1; // ~~~ but with F(s[i])
auto it=s.begin();++it;
for(int i=1,
last=s0 /* s[i-1] */;
it!=s.end();++i,last=*it++){
int diff=*it-last; // s[i]-s[i-1]
f1[i]=(
f0[i-1]+f1[i-1]
)%MOD;
f0[i]=(
f0[i-1]*(diff/2ull)+f1[i-1]*((diff-1)/2ull)
)%MOD;
}
std::cout<<(f0.back()+f1.back())%MOD<<'\n';
}
}
