#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}
 
struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T1,typename T2>
ostream &operator<<(ostream &os,const pair<T1,T2>&p){
    os<<p.first<<" "<<p.second;
    return os;
}
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}

template<typename T1,typename T2>
istream &operator>>(istream &is,pair<T1,T2>&p){
    is>>p.first>>p.second;
    return is;
}

template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

template<ll Mod>
struct ModInt{
    long long x;
    ModInt():x(0){}
    ModInt(long long y):x(y>=0?y%Mod:(Mod-(-y)%Mod)%Mod){}
    ModInt &operator+=(const ModInt &p){
        if((x+=p.x)>=Mod) x-=Mod;
        return *this;
    }
    ModInt &operator-=(const ModInt &p){
        if((x+=Mod-p.x)>=Mod)x-=Mod;
        return *this;
    }
    ModInt &operator*=(const ModInt &p){
        x=(int)(1ll*x*p.x%Mod);
        return *this;
    }
    ModInt &operator/=(const ModInt &p){
        (*this)*=p.inverse();
        return *this;
    }
    ModInt operator-()const{return ModInt(x);}
    ModInt operator+(const ModInt &p)const{return ModInt(*this)+=p;}
    ModInt operator-(const ModInt &p)const{return ModInt(*this)-=p;}
    ModInt operator*(const ModInt &p)const{return ModInt(*this)*=p;}
    ModInt operator/(const ModInt &p)const{return ModInt(*this)/=p;}
    ModInt operator==(const ModInt &p)const{return x==p.x;}
    ModInt operator!=(const ModInt &p)const{return x!=p.x;}
    ModInt inverse()const{
        int a=x,b=Mod,u=1,v=0,t;
        while(b>0){
            t=a/b;
            swap(a-=t*b,b);swap(u-=t*v,v);
        }
        return ModInt(u);
    }
    ModInt pow(long long n)const{
        ModInt ret(1),mul(x);
        while(n>0){
            if(n&1) ret*=mul;
            mul*=mul;n>>=1;
        }
        return ret;
    }
    friend ostream &operator<<(ostream &os,const ModInt &p){return os<<p.x;}
    friend istream &operator>>(istream &is,ModInt &a){long long t;is>>t;a=ModInt<Mod>(t);return (is);}
    static int get_mod(){return Mod;}
};
using mint=ModInt<mod>;


template<class INT>
struct Fraction{
    INT num,den;// numerator / denominator
    INT calc_gcd(INT a,INT b){
        return b?calc_gcd(b,a%b):a;
    }
    void normalize(){
        // INT g=calc_gcd(num,den);
        // num/=g;den/=g;
        // if(den<0)num=-num,den=-den;
    }
    Fraction(INT num=0,INT den=1):num(num),den(den){normalize();}
    long double to_ld()const{return (long double)num/den;}
    double to_d()const{return (double)num/den;}
    Fraction &operator+=(const Fraction &rhs){
        num=num*rhs.den+rhs.num*den;
        den*=rhs.den;
        normalize();
        return *this;
    }
    Fraction &operator-=(const Fraction &rhs){
        num=num*rhs.den-rhs.num*den;
        den*=rhs.den;
        normalize();
        return *this;
    }
    Fraction &operator*=(const Fraction &rhs){
        num*=rhs.num;
        den*=rhs.den;
        normalize();
        return *this;
    }
    Fraction &operator/=(const Fraction &rhs){
        num*=rhs.den;
        den*=rhs.num;
        normalize();
        return *this;
    }
    Fraction abs(){
        Fraction ret(*this);
        if(ret<0)ret.first=ret.first*(-1);
        return ret;
    }
    Fraction operator-(){(*this).first*=-1;return *this;}
    Fraction operator+=(const long long &rhs){(*this)+=Fraction(rhs);return *this;}
    Fraction operator-=(const long long &rhs){(*this)-=Fraction(rhs);return *this;}
    Fraction operator*=(const long long &rhs){(*this)*=Fraction(rhs);return *this;}
    Fraction operator/=(const long long &rhs){(*this)/=Fraction(rhs);return *this;}
    Fraction operator+(const Fraction &rhs)const{return Fraction(*this)+=rhs;}
    Fraction operator-(const Fraction &rhs)const{return Fraction(*this)-=rhs;}
    Fraction operator*(const Fraction &rhs)const{return Fraction(*this)*=rhs;}
    Fraction operator/(const Fraction &rhs)const{return Fraction(*this)/=rhs;}
    bool operator==(const Fraction &rhs)const{return num*rhs.den==den*rhs.num;}
    bool operator!=(const Fraction &rhs)const{return !(*this==rhs);}
    bool operator>=(const Fraction &rhs)const{return num*rhs.den>=den*rhs.num;}
    bool operator<=(const Fraction &rhs)const{return num*rhs.den<=den*rhs.num;}
    bool operator>(const Fraction &rhs)const{return num*rhs.den>den*rhs.num;}
    bool operator<(const Fraction &rhs)const{return num*rhs.den<den*rhs.num;}
    friend ostream &operator<<(ostream &os,const Fraction &p){return os<<p.num<<"/"<<p.den;}
};
using frac=Fraction<ll>;

int p,q,a,n;

inline void solve(){
    function<int(frac,int,int,int)> rec=[&](frac f,int rem,int denM,int mul){
        if(rem==0){
            if(f==0)return 1;
            else return 0;
        }
        if(f==0) return 1;
        int ret=0;
        for(int i=a/mul;i>=denM;i--){
            frac t(1,i);
            if(f<t)break;
            ret+=rec(f-t,rem-1,i,mul*i);
        }
        return ret;
    };
    cout<<rec(frac(p,q),n,1,1)<<"\n";
}

signed main(){
    while(cin>>p>>q>>a>>n,n)solve();
    return 0;
}



Measured memory_bytes: 3156