The pattern is +5, -2.
So it would be:
13+5=18
18-2=16
16+5=21
21-2=19
19+5=24
24
16.
what number comes next 1 -8 -16 -24 -33
the next answer would be 1,024
32
32
24, they are going up in 3's, 13, 16, 19 and 18, 21 so next number is 24.
The series 1 6 10 13 15 (1+5=6; 6+4=10, 10+3=13; 13+2=15) is completed by 15+1=16. The answer is 16.
16384
81
24
7
13