\\ Number of maximal subsets of {1..n} containing no sums or products of distinct elements.
\\ Main recursive function has the following arguments:
\\    k: Indicates elements from 2..k have been picked.
\\    b: bitmap of chosen elements.
\\    es: bitmap of sums of distinct elements of b.
\\    ep: bitmap of products of distinct elements of b.
A326025(n)={
   \\ test for maximality
    my(ismaxl(b, es, ep)=
      for(k=2, n, if(!bittest(es,k) && !bittest(ep,k) && !bitand(es, b>>k),
          my(f=0);
          for(i=2, n\k, if(bittest(ep,i) && bittest(b,k*i), f=1; break));
          if(!f, return(0));
       ));
      1
    );
    \\ main recursion
    my(recurse(k, b, es, ep)=
    k++;
    if(k > n, ismaxl(b, es, ep), 
      my(t = self()(k, b, es, ep));
      if(!bittest(es,k) && !bittest(ep, k),
         es = bitor(es, bitand((2<<n)-1, es << k));
         forstep(i=n\k, 1, -1, if(bittest(ep,i), ep=bitor(ep,1<<(k*i))));
         t += self()(k, b + (1<<k), es, ep);
      );
      t);
   );
   1 + if(n > 1, recurse(1, 0, 1, 2));
}

\\ End