#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>

#define rep(i, m, n) for(int i=int(m);i<int(n);i++)
#define EACH(i, c) for (auto &(i): c)
#define all(c) begin(c),end(c)
#define EXIST(s, e) ((s).find(e)!=(s).end())
#define SORT(c) sort(begin(c),end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())

//#define LOCAL 0
//#ifdef LOCAL
//#define DEBUG(s) cout << (s) << endl
//#define dump(x)  cerr << #x << " = " << (x) << endl
//#define BR cout << endl;
//#else
//#define DEBUG(s) do{}while(0)
//#define dump(x) do{}while(0)
//#define BR
//#endif


//改造
typedef long long int ll;
using namespace std;
#define INF (1 << 30) - 1
#define INFl (ll)5e15
#define DEBUG 0 //デバッグする時1にしてね
#define dump(x)  cerr << #x << " = " << (x) << endl
#define MOD 1000000007
//ここから編集する

/**
 * p / q
 */
struct Bunsuu {
    using T = ll;
    T p, q;

    Bunsuu(T p_, T q_) : p(p_), q(q_) {

    }

    Bunsuu(pair<T, T> aPair) : p(aPair.first), q(aPair.second) {

    }

    Bunsuu operator+(Bunsuu right) {
        T bunbo = q * right.q;
        T bunshi = p * right.q + right.p * q;
        return Bunsuu(yakubun(bunshi, bunbo));
    }

    Bunsuu operator-(Bunsuu right) {
        T bunbo = q * right.q;
        T bunshi = p * right.q - right.p * q;
        return Bunsuu(yakubun(bunshi, bunbo));
    }

    Bunsuu operator*(Bunsuu right) {
        T bunbo = q * right.q;
        T bunshi = p * right.p;
        return Bunsuu(yakubun(bunshi, bunbo));
    }

    Bunsuu operator/(Bunsuu right) {
        T bunbo = q * right.p;
        T bunshi = p * right.q;
        return Bunsuu(yakubun(bunshi, bunbo));
    }

    void print() {
        cout << p << "/" << q << endl;
    }

    ll gcd(ll a, ll b) {
        a = abs(a);
        b = abs(b);
        if (a < b) swap(a, b);
        if (a % b == 0) return b;

        return gcd(b, a % b);
    }

    pair<T, T> yakubun(T p, T q) {
        if (p == 0)return pair<T, T>(0ll, 1ll);
        T gcd_v = gcd(p, q);
        p /= gcd_v;
        q /= gcd_v;
        return pair<T, T>(p, q);
    }

    double value() {
        return 1.0 * p / q;
    }
};

ll dfs(Bunsuu bunsuu, Bunsuu a, int n, int low) {
    if (bunsuu.p == 0) {
        return 1;
    }
    if (bunsuu.value() < 0) return 0;
    if (n == 0) return 0;

    ll ret = 0;
    for (int i = low; i <= a.value(); i++) {
        Bunsuu tmp = Bunsuu(1, i);
        Bunsuu hantei = bunsuu - (tmp * Bunsuu(n,1));
        if(hantei.p > 0){
            break;
        }
        ret += dfs(bunsuu - tmp, a * tmp, n - 1, i);
    }
    return ret;
}

ll dfs(Bunsuu bunsuu, int a, int n) {
    return dfs(bunsuu, Bunsuu(a, 1), n, 1);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);


    while (true) {
        int p, q, a, n;
        cin >> p >> q >> a >> n;
        if (p == 0) break;
        cout << dfs(Bunsuu(p, q), a, n) << endl;
    }

    return 0;
}



Measured memory_bytes: 3020