upto(n) = {
	my(res = List(), target = 2, last1 = 25); 
	forfactored(i = 26, n, 
		if(bigomega(i[2]) == 2,
			r = i[1]%6;
			if(r == target,
				if(target == 5,
					listput(res, last1);
					target = 1
				,
					if(target == 1, 
						last1 = i[1];
					);
					target++;
				)
			,
				if(r == 1,
					last1 = i[1];
					target = 2
				,
					target = 1
				)
			)
		)
	);
	if(#res > 0 && res[#res] != last1 && is(last1),
		listput(res, last1)
	);
	res
}

is(n) = {
	if(n%6 != 1 || bigomega(n) != 2,
		return(0)	
	);
	my(target = 2);
	for(i = n + 1, oo,
		
		if(bigomega(i) == 2,
			if(i%6 == target,
				if(target == 5,
					return(1)
				,
					target++
				)
			,
				return(0)
			)
		)		
	)
}