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 | 4 |
| 2 | 14 |
| 3 | 50 |
| 4 | 180 |
| 5 | 658 |
| 6 | 2429 |
| 7 | 9052 |
| 8 | 33975 |
| 9 | 128320 |
| 10 | 487124 |
| 11 | 1857362 |
| 12 | 7108400 |
| 13 | 27293280 |
| 14 | 105090130 |
| 15 | 405643176 |
| 16 | 1569193041 |
| 17 | 6082113750 |
| 18 | 23615073305 |
| 19 | 91834287660 |
| 20 | 357631419474 |
| 21 | 1394521107804 |
| 22 | 5444070076494 |
| 23 | 21275915138100 |