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 | 5 |
| 2 | 53 |
| 3 | 458 |
| 4 | 3411 |
| 5 | 19865 |
| 6 | 95214 |
| 7 | 383714 |
| 8 | 1346183 |
| 9 | 4202086 |
| 10 | 11905966 |
| 11 | 31061806 |
| 12 | 75533056 |
| 13 | 172800689 |
| 14 | 374861365 |
| 15 | 775978710 |
| 16 | 1541027694 |
| 17 | 2949003213 |
| 18 | 5458806804 |
| 19 | 9805626744 |
| 20 | 17140511056 |