#include<bits/stdc++.h>
#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(a) (a).begin(),(a).end()
#define SZ(a) (int)(a).size()
#define FOR(i, a, b) for(int i=(a); i<=(b); ++i)
#define ROF(i, a, b) for(int i=(a); i>=(b); --i)
#define make_unique(a) sort(all((a))), (a).resize(unique(all((a)))-(a).begin())
using namespace std;
typedef pair<int,int> PII;
typedef long long LL;
typedef double DD;
typedef long double LD;
typedef pair<LL,LL> PLL;
typedef pair<DD,DD> PDD;
typedef vector<int> VI;
typedef vector<LL> VL;
const int N = 607;
const int mod = 1000000007;
void plusle(int &a, int b){
if((a+=b) >= mod) a -= mod;
}
int add(int a, int b){
return ((a+=b)>=mod) ? a-mod : a;
}
int mul(int a, int b){
return a * 1ll * b % mod;
}
int dp[N<<1][N];
int comp[N], freestyle[N];
int ranger[N];
int fac[N], inv[N], paskal[N][N];
int place[N][N>>1]; // pillars, sum
int power(int a, int b){
int ans = 1;
for(int i = 1; i <= b; i<<=1, a=mul(a,a)){
if(i&b) ans = mul(ans, a);
}
return ans;
}
void init(){
fac[0] = inv[0] = paskal[0][0] = 1;
FOR(i, 1, 600){
fac[i] = mul(fac[i-1], i);
inv[i] = power(fac[i], mod-2);
paskal[i][0] = 1;
FOR(j, 1, i) paskal[i][j] = add(paskal[i-1][j-1], paskal[i-1][j]);
}
//printf("[[[%d\n",paskal[2][2]);
FOR(i, 0, 300) place[0][i] = 1;
FOR(i, 1, 600){
FOR(j, 0, 300){
place[i][j] = 0;
if(j > 0) place[i][j] = mul( place[i-1][j], i );
if(i > 1) plusle( place[i][j], mul( mul(paskal[i][2], inv[2]), place[i-2][j+1] ) );
if(j > 1) plusle( place[i][j], place[i][j-1] );
}
}
//printf("place(2,0) %d\n",place[2][0]);
comp[1] = 1;
FOR(i, 2, 600) comp[i] = place[i][0];
FOR(i, 0, 300) place[0][i] = 1;
FOR(i, 1, 600){
FOR(j, 0, 300){
place[i][j] = 0;
place[i][j] = mul( place[i-1][j], i );
if(i > 1) plusle( place[i][j], mul( mul(paskal[i][2], inv[2]), place[i-2][j+1] ) );
if(j > 0) plusle( place[i][j], place[i][j-1] );
}
}
freestyle[0] = 1;
FOR(i, 1, 600) freestyle[i] = place[i][0];
//FOR(i, 0, 5){
// printf("comp %d = %d, free %d = %d\n",i,comp[i],i,freestyle[i]);
//}
FOR(i, 1, 600){
// have i arrange index
// make smth
FOR(j, 1, i){
// j is number of pillar in the first component
int v = mul( paskal[i-1][j-1], comp[j] );
int w = mul( freestyle[i-j], v );
plusle( ranger[i], w );
}
//if(i <= 5) printf("[%d] %d\n",i,ranger[i]);
}
}
int mark[N<<1];
void solve(){
int n;
init();
scanf("%d",&n);
FOR(i,1,n){
int a;
scanf("%d",&a);
mark[a] = 1;
}
dp[(n<<1)+1][0] = 1;
int Fcnt, Rcnt;
Fcnt = Rcnt = 0;
ROF(i, n<<1, 1){
if(mark[i]){
FOR(j, 0, Rcnt-Fcnt){
int remain = Rcnt - Fcnt - j;
ROF(k, j, 0){
int use = j-k;
int v = mul( paskal[j][use], ranger[use+1] );
plusle(dp[i][k], mul( dp[i+1][j], v ) );
}
}
FOR(j, 0, Rcnt-Fcnt){
plusle( dp[i][j+1], dp[i+1][j] );
}
++Rcnt;
}else{
FOR(j, 0, Rcnt-Fcnt-1){
int remain = Rcnt - Fcnt - j;
dp[i][j] = mul(dp[i+1][j], remain);
}
++Fcnt;
}
//FOR(j, 0, Rcnt-Fcnt){
// printf("(%d, %d) = %d\n",i,j,dp[i][j]);
//}
}
printf("%d",dp[1][0]);
}
int main(){
solve();
return 0;
}
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