Question 1091784
<br>You can put any number next and it will be a valid sequence.  So it is impossible to know if any answer you come up with is "right" in a problem like this.<br>
However, there is a nice pattern in these numbers that suggests a PROBABLE next number:<br>
5 to the next number, 11: double and add 1
11 to the next number, 21: double and subtract 1
21 to the next number, 43: [put your answer here]
43 to the next number, __: [put your answer here]