Hardcoding the Cops and Robbers (Cops) This is a cops-and-robbers challenge. The robbers' thread is here.

An interesting question to think about is the following:


  If I have a sequence of numbers how many of them do I have to provide before it is clear what sequence I am talking about?


For example if I want to talk about the positive integers in order starting from \$1\$, I could say \$1,2,3, \dots\$, but is that really enough?

I have one way of answering this question, and being a code-golfer it involves code-golf.  You have provided enough terms of a sequence if the shortest code that produces those terms produces all the terms of the sequence.  If we think about this in terms of code-golf, this would mean you have provided enough test cases such that the shortest code that passes the test-cases does the desired task.

Challenge

This challenge is a cops-and-robbers challenge.  In which cops will be presenting test-cases and robbers will have to find a shorter way to spoof the test-cases other than the intended sequence. Cops will present the following things:


A piece of code that takes a non-negative integer as input and produces an integer as output.    This code will define your sequence. Your code does not need to support 0 as an input, opting to instead take 1 as the smallest input.  It should be clear if this is the case in your answer.
Any relevant platform or language requirements that might affect the output, for example the size of longint.
A number \$n\$, along with the first \$n\$ terms of the sequence as calculated by the code.  These will act as "test-cases".


You are encouraged to explain what your sequence does and link OEIS if it exists, however it is your code that defines the sequence not the description.

Robbers will be finding a program in the same language that is shorter than the one presented and passes all the test cases (produces the same output for the first \$n\$ inputs as the cop's code). The robber's code must also differ in output from the cop's program for some number larger than \$n\$.

Cops must be able to crack their own answers before submitting them.

After one week a cop may reveal their crack and mark their answer as Safe.  Answers marked as such can no longer be cracked.

Scoring

Cops answers will be scored by the number of bytes with fewer bytes being better. Cracked answers score an infinite score.
cQuents, 4 bytes (Cracked)

"::$


Try it online!

Here are eight (n=8) cases:

1 1
2 12
3 123
4 1234
5 12345
6 123456
7 1234567
8 12345678


Code explanation:

"      Stringify sequence (join on "", remove it and see what happens)
 ::    Given input n, output all items in the sequence up to and including n
   $   Each item in the sequence equals the index


So the sequence is 1,2,3,4,5 ..., it is joined on "" so it becomes 12345 ..., and :: means that it prints up to the input.