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 | 21 |
| 2 | 301 |
| 3 | 3681 |
| 4 | 41461 |
| 5 | 445641 |
| 6 | 4658221 |
| 7 | 47871201 |
| 8 | 486836581 |
| 9 | 4919066361 |
| 10 | 49504632541 |
| 11 | 496978967121 |
| 12 | 4981629662101 |
| 13 | 49888557269481 |
| 14 | 499325240101261 |
| 15 | 4995920923029441 |
| 16 | 49975372950286021 |
| 17 | 499851474762263001 |
| 18 | 4999105033876312381 |
| 19 | 49994611129771546161 |