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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 30 |
| 5 | 180 |
| 6 | 462 |
| 7 | 890 |
| 8 | 1532 |
| 9 | 3385 |
| 10 | 19871 |
| 11 | 29040 |
| 12 | 31545 |
| 13 | 597311 |
| 14 | 1293698 |
| 15 | 2279181 |
| 16 | 118374763 |
| 17 | 821495413 |
| 18 | 2247521689 |
| 19 | 3145845927 |
| 20 | 7650216016 |
| 21 | 22859974504 |
| 22 | 78076882908 |
| 23 | 189573830057 |
| 24 | 223393027147 |
| 25 | 435001965071 |
| 26 | 637259184969 |
| 27 | 821040118481 |
| 28 | 1562199136511 |