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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 22 |
| 6 | 86 |
| 7 | 414 |
| 8 | 2521 |
| 9 | 19494 |
| 10 | 191695 |
| 11 | 2397716 |
| 12 | 38148444 |
| 13 | 772057396 |
| 14 | 19875413009 |
| 15 | 650843469738 |
| 16 | 27110077916903 |
| 17 | 1436411242814058 |
| 18 | 96810095832996034 |
| 19 | 8299583912379548210 |
| 20 | 905077596297808256825 |
| 21 | 125547805293905152853710 |
| 22 | 22152679283963321048140511 |