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 | 4847 |
| 10 | 16660 |
| 11 | 57820 |
| 12 | 202086 |
| 13 | 709928 |
| 14 | 2503266 |
| 15 | 8850681 |
| 16 | 31355020 |
| 17 | 111242127 |
| 18 | 395091069 |
| 19 | 1404332528 |
| 20 | 4994581900 |
| 21 | 17771328588 |
| 22 | 63253477326 |
| 23 | 225194224134 |
| 24 | 801884971816 |
| 25 | 2855809269782 |
| 26 | 10171707099565 |