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) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 20 |
| 6 | 97 |
| 7 | 550 |
| 8 | 3794 |
| 9 | 29826 |
| 10 | 266527 |
| 11 | 2649156 |
| 12 | 29040865 |
| 13 | 347548542 |
| 14 | 4509961264 |
| 15 | 63050417976 |
| 16 | 944767674590 |
| 17 | 15103712944100 |
| 18 | 256594870255076 |
| 19 | 4616238126871328 |
| 20 | 87670085904641440 |
| 21 | 1752759735606185804 |
| 22 | 36796608121601906104 |
| 23 | 809312755145598475440 |
| 24 | 18609995953274373396982 |