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 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 11 |
| 7 | 37 |
| 8 | 123 |
| 9 | 401 |
| 10 | 1281 |
| 11 | 4023 |
| 12 | 12461 |
| 13 | 38175 |
| 14 | 115939 |
| 15 | 349701 |
| 16 | 1049063 |
| 17 | 3133493 |
| 18 | 9327357 |
| 19 | 27687947 |
| 20 | 82009215 |
| 21 | 242473197 |
| 22 | 715889685 |
| 23 | 2111215763 |
| 24 | 6220468653 |
| 25 | 18314669783 |
| 26 | 53892395679 |
| 27 | 158512474561 |
| 28 | 466071547105 |