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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 44 |
| 6 | 168 |
| 7 | 717 |
| 8 | 3360 |
| 9 | 17091 |
| 10 | 93492 |
| 11 | 545670 |
| 12 | 3372738 |
| 13 | 21911216 |
| 14 | 148486735 |
| 15 | 1041923520 |
| 16 | 7518618028 |
| 17 | 55460237723 |
| 18 | 416078640459 |
| 19 | 3161904730760 |
| 20 | 24261222270154 |
| 21 | 187499556005523 |
| 22 | 1456815538485716 |
| 23 | 11363752138036864 |