-3, -6, -11
28
27
15
The next number in the sequence 3-15-6-30-21 is -207.
12
Sequence is +4 - 3 + 5 - 2 + 6 - 1 (+1 - 1)2 6 3 8 6 12 next number 11
8 -1 then +3
The next number in the sequence is 18. It's +1, +2, +3, +4, ....
-3, -6, -11
The next term in the sequence (not the next sequence) is 76.It is obtained by using n= 6 int(n) = (29n4 - 338n3 + 1363n2 - 2158n + 1128)/24 for n = 1, 2, 3, etc
7
28
Zero
27
15
27