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 | 8 |
| 3 | 66 |
| 4 | 560 |
| 5 | 4845 |
| 6 | 42504 |
| 7 | 376740 |
| 8 | 3365856 |
| 9 | 30260340 |
| 10 | 273438880 |
| 11 | 2481256778 |
| 12 | 22595200368 |
| 13 | 206379406870 |
| 14 | 1889912732400 |
| 15 | 17345898649800 |
| 16 | 159518999862720 |
| 17 | 1469568786235308 |
| 18 | 13559593014190944 |
| 19 | 125288932441604200 |