Clues are everywhere

$F(n)=F(n-1)+F(n-2)-1$ ,we need $F(7)$ , so $n=7$ :-

$F(7)=F(6)+F(5)-1=9+6-1=14$

Each number is 1 less than the sum of the 2 previous numbers. Ed Gray

There are two similar ways to solve this (to my knowledge).

The first is that each term is 1+ than the numbers in the Fibonacci sequence.

Fibonacci sequence : 1, 1, 2, 3, 5, 8, 13

COPIED Sequence : 1+1, 1+1, 2+1, 3+1, 5+1, 8+1, 13+1

Given this the answer is 14.

The second one is: It functions like the Fibonacci sequence but if it starts with n, n then the next term is 2n-1

2+2-1=3

2+3-1=4

3+4-1=6

4+6-1=9

6+9-1=14

Given this the answer is 14.