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 | 3 |
| 4 | 9 |
| 5 | 24 |
| 6 | 99 |
| 7 | 418 |
| 8 | 1769 |
| 9 | 9320 |
| 10 | 49541 |
| 11 | 278912 |
| 12 | 1764825 |
| 13 | 11319784 |
| 14 | 77850287 |
| 15 | 570610472 |
| 16 | 4290387409 |
| 17 | 34316005632 |
| 18 | 285335249065 |
| 19 | 2455224885440 |
| 20 | 22165590003849 |
| 21 | 206191758121856 |
| 22 | 1989511661589435 |
| 23 | 19903718061574144 |
| 24 | 204795484665487865 |
| 25 | 2179948112062667392 |