List the next three terms in the following sequence:

1, 2, 4, 7, 11, 16,...

Also list the number that would be the twentieth number in the sequence.
a.
23, 31, 40; 200
b.
23, 31, 40; 191
c.
22, 28, 35; 185
d.
22, 29, 37; 191