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

a = vector(1 000)
mx = 2*#a

find(n) = {
	my (p=vector(n));
	for (v=unseen, mx,
		if (!seen(v),
			ok=1;
			p[1]=v;
			for (k=2, n,
				p[k]=p[k-1]*a[n-k+1];
				if (p[k]<=mx && seen(p[k]),
					ok=0;
					break;
				);
			);
			if (ok,
				for (i=1, n-1,
					my (q=1);
					for (j=i, n-1,
						q*=a[j];
						if (setsearch(p,q),
							ok=0;
							break;
						);
					);
				);
			);
			if (ok,
				for (k=1, n,
					if (p[k]>mx, break, see(p[k]));
				);
				return (v);
			);
		);
	);
	quit
}

{
	see(1);
	for (n=1, #a,
		print (n " " a[n] = find(n));
	);
}

quit