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 | 8 |
| 4 | 55 |
| 5 | 370 |
| 6 | 2520 |
| 7 | 17472 |
| 8 | 123151 |
| 9 | 880070 |
| 10 | 6360706 |
| 11 | 46402312 |
| 12 | 341153384 |
| 13 | 2524722928 |
| 14 | 18789734496 |
| 15 | 140521154048 |
| 16 | 1055383259791 |
| 17 | 7956220907758 |
| 18 | 60179579570382 |
| 19 | 456545145078408 |
| 20 | 3472804505717170 |