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) |
|---|---|
| 3 | 6 |
| 4 | 36 |
| 5 | 200 |
| 6 | 1170 |
| 7 | 7392 |
| 8 | 50568 |
| 9 | 372528 |
| 10 | 2936070 |
| 11 | 24617120 |
| 12 | 218521116 |
| 13 | 2045278248 |
| 14 | 20112821274 |
| 15 | 207162957120 |
| 16 | 2228888801040 |
| 17 | 24989309310944 |
| 18 | 291322555295886 |
| 19 | 3524580202643136 |
| 20 | 44176839081266340 |
| 21 | 572725044269255640 |