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 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 42 |
| 6 | 132 |
| 7 | 429 |
| 8 | 1429 |
| 9 | 4852 |
| 10 | 16730 |
| 11 | 58422 |
| 12 | 206192 |
| 13 | 734332 |
| 14 | 2635680 |
| 15 | 9524301 |
| 16 | 34622207 |
| 17 | 126520393 |
| 18 | 464517300 |
| 19 | 1712650520 |
| 20 | 6338433840 |
| 21 | 23538973950 |
| 22 | 87690410580 |
| 23 | 327611738790 |
| 24 | 1227178265182 |
| 25 | 4607940112396 |
| 26 | 17341126763366 |
| 27 | 65395548619912 |