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 | 2 |
| 4 | 4 |
| 5 | 20 |
| 6 | 20 |
| 7 | 140 |
| 8 | 280 |
| 9 | 280 |
| 10 | 280 |
| 11 | 3080 |
| 12 | 3080 |
| 13 | 40040 |
| 14 | 40040 |
| 15 | 40040 |
| 16 | 80080 |
| 17 | 1361360 |
| 18 | 1361360 |
| 19 | 25865840 |
| 20 | 25865840 |
| 21 | 25865840 |
| 22 | 25865840 |
| 23 | 594914320 |
| 24 | 594914320 |
| 25 | 2974571600 |
| 26 | 2974571600 |
| 27 | 2974571600 |
| 28 | 2974571600 |
| 29 | 86262576400 |