upto(n) = {my(d = [1,1], res = List(), vs, ds);
while(1,
	vs = vecsum(d); 
	if(vs % 2 == 0 && !hassum(freqdigits(d), vs/2) && vecsort(d) == d, 
		
			ds = fromdigits(d);
			if(ds > n, return(res));
			listput(res, ds);		
			
	);
	d = digits(fromdigits(d) + 1);
)

}

addhelp(hassum, "See if some sum of elements listed by index in v give sum n. v[i] gives the frequency of a number i. v might be found with function freqdigits.");
hassum(v, n, {l = 1}) = {my(cv); 
	if(n == 0, return(1));  
	for(i = l, #v, 
		if(i > n, next(1)); 
		cv = v; 
		if(cv[i] > 0, 
			cv[i]--;
			if(hassum(cv, n - i, i) == 1, return(1));
			
		) 	
	)
}

addhelp(freqdigits, "give a vector with 9 elements res[i] where res[i] gives the frequecy of digit i in n, ignoring 0's. (adapted to have input of vector with digits.)");
freqdigits(d) = {my( res = List(vector(10))); \\ d = digits(n),
	for(i = 1, #d, 
		res[d[i]+1]++;
	); listpop(res, 1); res
}