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 | 8 |
| 3 | 21 |
| 4 | 54 |
| 5 | 144 |
| 6 | 404 |
| 7 | 1195 |
| 8 | 3712 |
| 9 | 12000 |
| 10 | 39994 |
| 11 | 136400 |
| 12 | 473430 |
| 13 | 1665868 |
| 14 | 5926476 |
| 15 | 21275805 |
| 16 | 76964808 |
| 17 | 280250088 |
| 18 | 1026309908 |
| 19 | 3777411342 |
| 20 | 13965286180 |
| 21 | 51837285776 |
| 22 | 193107846304 |
| 23 | 721732334136 |
| 24 | 2705480787422 |
| 25 | 10169387310362 |
| 26 | 38320472420462 |
| 27 | 144733083435688 |