s = 0
unseen = 1
seen(v) = bit test(s, v)
see(v) = s = bit or(s, 2^v); while (seen(unseen), unseen++)

other(ppp,pp,p) = {
	my (f=factor(pp), v=oo);

	for (k=1, #f~,
		forstep (c=ceil(unseen/f[k,1])*f[k,1], v, f[k,1],
			if (!seen(c) && gcd(ppp*p,c)==1,
				v = min(v, c);
				break;
			);
		);
	);

	return (v);
}

{
	a = vector(20 000);
	m = 1;

	for (n=1, oo,
		if (n<=3,
				v = unseen,
				v = other(ppp,pp,p);
		);
		see(v);

		if (v<=#a,
			a[v] = n;

			while (a[m],
				print (m " " a[m]);
				if (m++ > #a,
					break (2);
				);
			);
		);

		[ppp,pp,p]=[pp,p,v];
	);
}

quit