// Slower C++ solution:
/*

                ____________    ______________       __

               / _________  /\ /_____   _____/\     / /\

              / /\       / /  \\    /  /\    \ \   / /  \

             / /  \_____/ /   / \__/  /  \____\/  / /   /

            / /   /    / /   /    /  /   /       / /   /

           / /   /    / /   /    /  /   /       / /   /

          / /   /    / /   /    /  /   /       / /   /

         / /___/____/ /   /    /  /   /       / /___/________

        /____________/   /    /__/   /       /______________/\

        \            \  /     \  \  /        \              \ \

         \____________\/       \__\/          \______________\/

           ___       ___               ___    __________

          /  /\     /  /\             /  /\  /_______  /\

         /  /__\___/  /  \           /  /  \ \      /  /  \

        /____    ____/   /          /  /   /  \____/  /   /

        \   /   /\   \  /          /  /   /       /  /   /

         \_/   /  \___\/ ___      /  /   /       /  /   /

          /   /   /     /  /\    /  /   /       /  /   /

         /   /   /     /  /__\__/  /   /       /  /___/____

        /___/   /     /___________/   /       /___________/\

        \   \  /      \           \  /        \           \ \

         \___\/        \___________\/          \___________\/



          A FAN OF FIZZYDAVID



*/



#include<bits/stdc++.h>



#define HEAP priority_queue

#define rep(i,n) for(int i=0;i<(n);i++)

#define per(i,n) for(int i=(n)-1;i>=0;i--)

#define forn(i,l,r) for(int i=(l);i<=(r);i++)

#define nrof(i,r,l) for(int i=(r);i>=(l);i--)

#define mp make_pair

#define mt make_tuple

#define pb push_back

#define X first

#define Y second

#define eps 1e-6

#define pi 3.1415926535897932384626433832795

#define orz int

#define yjz main

#define fizzydavid return

#define ak 0

#define la ;

#define SZ(x) (int)x.size()

#define ALL(x) x.begin(),x.end()

#define FILL(a,b) memset((a),(b),sizeof((a)))



using namespace std;



typedef long long LL;

typedef double flt;

typedef vector<int> vi;

typedef pair<int,int> pii;

typedef vector<LL> vl;

typedef pair<int,LL> pil;

typedef pair<LL,int> pli;

typedef pair<LL,LL> pll;

typedef vector<pil> vil;

typedef vector<pii> vii;



const int iinf=1e9+7;

const LL linf=1ll<<60;

const flt dinf=1e10;



template <typename T>

inline void scf(T &x)

{

	bool f=0; x=0; char c=getchar();

	while((c<'0' || c>'9') && c!='-') c=getchar();

	if(c=='-') { f=1; c=getchar(); }

	while(c>='0' && c<='9') { x=x*10+c-'0'; c=getchar(); }

	if(f) x=-x; return;

}



template <typename T1,typename T2>

void scf(T1 &x,T2 &y) { scf(x); return scf(y); }



template <typename T1,typename T2,typename T3>

void scf(T1 &x,T2 &y,T3 &z) { scf(x); scf(y); return scf(z); }



template <typename T1,typename T2,typename T3,typename T4>

void scf(T1 &x,T2 &y,T3 &z,T4 &w) { scf(x); scf(y); scf(z); return scf(w); }



#ifdef ONLINE_JUDGE

#define debug(x,c) ;

#else

#define DEBUG

#define debug(x,c) cerr<<#x<<"="<<x<<c;

#endif



//---------------------------head----------------------------



const int N = 2333;

const LL mod = 1e9 + 7ll;



int n, k;

LL dp[N][N];



orz yjz()

{

    scf(n, k);

    dp[1][1] = 1ll;

    forn(i, 2, n) forn(j, 1, i) dp[i][j] = (dp[i - 1][j] + dp[i][j - 1]) % mod;

    LL ans = dp[n][k];

    rep(_, n - k - 1) (ans *= 2) %= mod;

    printf("%lld\n", ans);

	fizzydavid ak la

}


// Faster C++ solution for the same problem (measured speedup: 4.690673539179977x):
#include<cstdio>

#define F(i,l,r) for(int i=l;i<=r;i++)

int m=1e9+7,n,k,d[2333][2333];main(){scanf("%d%d",&n,&k);d[1][1]=1;F(i,2,n)F(j,1,i)d[i][j]=(d[i][j-1]+d[i-1][j])%m;F(i,1,n-k-1)(d[n][k]*=2)%=m;printf("%d\n",d[n][k]);}