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 | 0 |
| 2 | 2 |
| 3 | 8 |
| 4 | 31 |
| 5 | 130 |
| 6 | 590 |
| 7 | 2798 |
| 8 | 13541 |
| 9 | 66724 |
| 10 | 332708 |
| 11 | 1673536 |
| 12 | 8479367 |
| 13 | 43218034 |
| 14 | 221383712 |
| 15 | 1138976166 |
| 16 | 5882112985 |
| 17 | 30479772624 |
| 18 | 158413903096 |
| 19 | 825556260636 |
| 20 | 4312814257059 |
| 21 | 22580855859166 |
| 22 | 118468635595680 |
| 23 | 622698941708890 |