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 | 9 |
| 2 | 21 |
| 3 | 48 |
| 4 | 111 |
| 5 | 255 |
| 6 | 588 |
| 7 | 1353 |
| 8 | 3117 |
| 9 | 7176 |
| 10 | 16527 |
| 11 | 38055 |
| 12 | 87636 |
| 13 | 201801 |
| 14 | 464709 |
| 15 | 1070112 |
| 16 | 2464239 |
| 17 | 5674575 |
| 18 | 13067292 |
| 19 | 30091017 |
| 20 | 69292893 |
| 21 | 159565944 |
| 22 | 367444623 |
| 23 | 846142455 |
| 24 | 1948476324 |
| 25 | 4486903689 |
| 26 | 10332332661 |
| 27 | 23793043728 |
| 28 | 54790041711 |