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 | 3 |
| 2 | 10 |
| 3 | 20 |
| 4 | 70 |
| 5 | 126 |
| 6 | 462 |
| 7 | 792 |
| 8 | 3003 |
| 9 | 5005 |
| 10 | 19448 |
| 11 | 31824 |
| 12 | 125970 |
| 13 | 203490 |
| 14 | 817190 |
| 15 | 1307504 |
| 16 | 5311735 |
| 17 | 8436285 |
| 18 | 34597290 |
| 19 | 54627300 |
| 20 | 225792840 |
| 21 | 354817320 |
| 22 | 1476337800 |
| 23 | 2310789600 |
| 24 | 9669554100 |
| 25 | 15084504396 |
| 26 | 63432274896 |
| 27 | 98672427616 |