Such as: 1, 4, 9, 16, ...
Comparison 1, 2, 3, 4, ....
Obviously a (n) = n 2.
2. Compare the sum of the figures before and after.
Such as: 1, 1, 2, 3, 5, 8, .......
Obviously, the sum of the first two is equal to the third, a(n)=a(n-2)+a(n- 1), (n & gt=3). (Fibonacci series)
Another example is: 1, 2,4,7, 1 1, 16. .....
Is the former term plus the natural sequence equals the latter term. a(n)=a(n- 1)+(n- 1),(n & gt=2).
Another example is:
3,4,6,9, 13 ....
3,4,6,9, 14 ....
Look at these two series, and then how to write?
The first one is: adding natural sequence; The second is the addition of the first two items-1. So write it down as follows:
3,4,6,9, 13, 18,24 ....
3,4,6,9, 14,22,35 ....
3. Look at the relationship between things.
Such as 1, 1, 3, 4, 5, 9, 7, 16. ....
If viewed separately, it is: 1, 3, 5, 7 and 1, 4, 9, 16.
Singular numbers are odd columns, and even numbers are the squares of natural numbers.
A lot, just say these simple things, I hope I can help you.