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 | 5 |
| 2 | 15 |
| 3 | 55 |
| 4 | 190 |
| 5 | 671 |
| 6 | 2353 |
| 7 | 8272 |
| 8 | 29056 |
| 9 | 102091 |
| 10 | 358671 |
| 11 | 1260143 |
| 12 | 4427294 |
| 13 | 15554592 |
| 14 | 54648506 |
| 15 | 191998646 |
| 16 | 674555937 |
| 17 | 2369942427 |
| 18 | 8326406594 |
| 19 | 29253473175 |
| 20 | 102777312308 |
| 21 | 361091343583 |
| 22 | 1268635610806 |
| 23 | 4457144547354 |