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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 25 |
| 6 | 91 |
| 7 | 390 |
| 8 | 1797 |
| 9 | 9069 |
| 10 | 49106 |
| 11 | 284537 |
| 12 | 1751554 |
| 13 | 11406588 |
| 14 | 78254594 |
| 15 | 563642925 |
| 16 | 4249337018 |
| 17 | 33443545866 |
| 18 | 274130245342 |
| 19 | 2335311549498 |
| 20 | 20637538548167 |
| 21 | 188867393030394 |
| 22 | 1787189672368355 |
| 23 | 17461684290203403 |
| 24 | 175930808241047092 |
| 25 | 1825666076751872506 |