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 | 3 |
| 2 | 54 |
| 3 | 126 |
| 4 | 294 |
| 5 | 672 |
| 6 | 1536 |
| 7 | 3552 |
| 8 | 8214 |
| 9 | 19092 |
| 10 | 44376 |
| 11 | 103200 |
| 12 | 240000 |
| 13 | 558000 |
| 14 | 1297350 |
| 15 | 3015990 |
| 16 | 7011366 |
| 17 | 16299318 |
| 18 | 37891014 |
| 19 | 88085676 |
| 20 | 204773784 |
| 21 | 476041212 |
| 22 | 1106661366 |
| 23 | 2572675992 |
| 24 | 5980747104 |
| 25 | 13903551072 |
| 26 | 32321836896 |
| 27 | 75139155000 |