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 | 3 |
| 3 | 10 |
| 4 | 35 |
| 5 | 126 |
| 6 | 462 |
| 7 | 1709 |
| 8 | 6371 |
| 9 | 23905 |
| 10 | 90178 |
| 11 | 341705 |
| 12 | 1299662 |
| 13 | 4958968 |
| 14 | 18973111 |
| 15 | 72763785 |
| 16 | 279636451 |
| 17 | 1076635399 |
| 18 | 4151948115 |
| 19 | 16035014604 |
| 20 | 62009441410 |
| 21 | 240083933750 |
| 22 | 930547077155 |
| 23 | 3610295962089 |
| 24 | 14019766334990 |
| 25 | 54487995870126 |
| 26 | 211931334450696 |