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 | 45 |
| 12 | 165 |
| 13 | 495 |
| 14 | 1287 |
| 15 | 3003 |
| 16 | 6435 |
| 17 | 12870 |
| 18 | 207350 |
| 19 | 1782638 |
| 20 | 10852478 |
| 21 | 52422578 |
| 22 | 213586658 |
| 23 | 762311978 |
| 24 | 2445069626 |
| 25 | 7177825511 |
| 26 | 167072419775 |
| 27 | 2041472747275 |
| 28 | 17401832788275 |
| 29 | 116094500641665 |
| 30 | 645070724513865 |
| 31 | 3103383925397925 |