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 | 4 |
| 3 | 17 |
| 4 | 98 |
| 5 | 622 |
| 6 | 4512 |
| 7 | 35373 |
| 8 | 300974 |
| 9 | 2722070 |
| 10 | 26118056 |
| 11 | 263266346 |
| 12 | 2780054884 |
| 13 | 30586452652 |
| 14 | 349724463584 |
| 15 | 4141218303165 |
| 16 | 50678688359190 |
| 17 | 639387728054310 |
| 18 | 8302396672724280 |
| 19 | 110754894628585950 |