0, 1, 2, 4, 6, 9, 12, 16, ?
What number should replace the question mark?
Choices.
A) 24
B) 20
C) 19
D) 26
E) 47
20   20   add 1, 1, 2, 2, 3, 3, 4, 4.
<result>B</result>
0, 1, 2, 4, 6, 9, 12, 16, ?
What number should replace the question mark?