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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 1 |
| 10 | 9 |
| 11 | 54 |
| 12 | 219 |
| 13 | 714 |
| 14 | 2001 |
| 15 | 5004 |
| 16 | 11439 |
| 17 | 24309 |
| 18 | 48619 |
| 19 | 831384 |
| 20 | 9069651 |
| 21 | 64369341 |
| 22 | 355150566 |
| 23 | 1635163542 |
| 24 | 6542615421 |
| 25 | 23369110326 |
| 26 | 75953123676 |
| 27 | 227864057851 |
| 28 | 5742168041637 |
| 29 | 90830731860000 |
| 30 | 920922875075934 |
| 31 | 7159714782188364 |