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 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 24 |
| 4 | 80 |
| 5 | 224 |
| 6 | 704 |
| 7 | 1920 |
| 8 | 5632 |
| 9 | 15360 |
| 10 | 43008 |
| 11 | 114688 |
| 12 | 315392 |
| 13 | 827392 |
| 14 | 2211840 |
| 15 | 5767168 |
| 16 | 15138816 |
| 17 | 38928384 |
| 18 | 100925440 |
| 19 | 256901120 |
| 20 | 657457152 |
| 21 | 1660944384 |
| 22 | 4202692608 |
| 23 | 10527703040 |
| 24 | 26424115200 |
| 25 | 65699577856 |
| 26 | 163477192704 |
| 27 | 403995361280 |
| 28 | 998043025408 |