This question already has an answer here:
The following is the rhombus sequence.
1 121 12321 1234321 123454321 12345654321 1234567654321 123456787654321 12345678987654321
Your task is to output this, taking no input and using standard output methods (STDOUT, list of numbers or list of strings, etc.).
There's a hitch. You may only use up to one loop - no nested loops. Recursion counts as a loop, so you can either recurse or loop, not both. Non-standard languages will be dealt with on a case-by-case basis.