9, 9, 18, 9, 17, 8, 15, 6, 11, 2, 3, 5, 8, 13, 4, 7...
There is a pattern that shows the next number(s). Find what it is and say what the next three are.

(In reply to

Answer by K Sengupta)

The third term (18) of the given sequence is obtained by adding the digits 9 and 9 inclusive of the first two terms.

Each of the other terms from the 4th term onwards are obtained by adding the two digits appearing to the left of a given term.

For example, the digits 7 and 8 appears to the left of the seventh term. Thus, the seventh term is equal to: 7+8 = 15.

Accordingly, proceeding in a similar manner, we must have:

The 17th term = 4+7 = 11, and:

The 18th term = 1+1 = 2, and:

The 19th term = 1+2 = 3.

Consequently, the required next three numbers are 11, 2 and 3.