This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 145 |
| 4 | 2905 |
| 5 | 65121 |
| 6 | 1563561 |
| 7 | 39322929 |
| 8 | 1022586105 |
| 9 | 27272680705 |
| 10 | 741894295369 |
| 11 | 20504949587409 |
| 12 | 574176887116441 |
| 13 | 16254518495907745 |
| 14 | 464436319229036265 |
| 15 | 13376293681432402545 |
| 16 | 387925710986712480825 |