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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 22 |
| 7 | 114 |
| 8 | 696 |
| 9 | 4923 |
| 10 | 39612 |
| 11 | 357900 |
| 12 | 3588836 |
| 13 | 39556420 |
| 14 | 475392840 |
| 15 | 6187284605 |
| 16 | 86701097310 |
| 17 | 1301467245330 |
| 18 | 20835850494474 |
| 19 | 354382860600678 |
| 20 | 6381494425302864 |
| 21 | 121290065781743383 |
| 22 | 2426510081356069016 |
| 23 | 50969474697328055064 |
| 24 | 1121571023472780698152 |