https://projecteuler.net/problem=853 有用的素数只有8个，随便搜。

PE853.cpp

#include <lastweapon/io>
#
using namespace lastweapon;

const int PMAX = 10000;
VI P; bitset<PMAX> isC;
#define ii (i*P[j])
void sieve(){
    FOR(i, 2, PMAX){
        if (!isC[i]) P.PB(i);
        for (int j=0;j<SZ(P)&&ii<PMAX;++j){
            isC[ii]=1; if (!(i%P[j])) break;
        }
    }
}
#undef ii

const int N = 121;
int f[N];

int a(int n) {
    f[0] = 0, f[1] = 1 % n;
    set<PII> S; S.insert({f[0], f[1]});
    FOR_1(i, 2, 121) {
        f[i] = (f[i-1] + f[i-2]) % n; PII p = {f[i-1], f[i]};
        if (CTN(S, p)) return i-1;
        S.insert(p);
    }
    return 0;
}

LL z = 0;

void dfs(LL n = 1, int k = 0, int an = 1) {
    //cout<<n << " " << k << " " << an << endl;
    if (!an || k >= SZ(P)) {
        return;
    } else {
        int p = P[k++], pp = p, ap = a(p); dfs(n, k, an);
        if (ap == 0) return;
        while (ap <= 120) {
            int t = lcm(an, ap); if (!t || 120 % t) break;
            if (n*pp>1000000000) break;
            if (t == 120) {
                //cout << n*pp << " " << ap << " " << p << endl;
                z += n*pp;
            }
            dfs(n*pp, k, t); pp *= p; ap *= p;
        }
    }
}

int main() {

#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    //freopen("/Users/minakokojima/Documents/GitHub/ACM-Training/Workspace/out.txt", "w", stdout);
#endif

    //REP_1(i, 120) cout << a(i) << endl;
    sieve();
    cout << SZ(P) << endl;
    VI PP = P; P.clear();
    for (auto p: PP) {
        //if (p>5 && ((p-1)%120) && ((2*p+2)%120)) {
        //} else {
        int ap = a(p);
        if (ap && !(120%ap)) {
            cout << p << endl;
            P.PB(p);
        }
    }
    cout << SZ(P) << endl;
    dfs();
    cout << z << endl;

}