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 | 5 |
| 3 | 12 |
| 4 | 31 |
| 5 | 84 |
| 6 | 245 |
| 7 | 752 |
| 8 | 2413 |
| 9 | 7991 |
| 10 | 27104 |
| 11 | 93605 |
| 12 | 327886 |
| 13 | 1161735 |
| 14 | 4155323 |
| 15 | 14982399 |
| 16 | 54393829 |
| 17 | 198666117 |
| 18 | 729443563 |
| 19 | 2690890444 |
| 20 | 9968312790 |
| 21 | 37066929338 |
| 22 | 138304185107 |
| 23 | 517646986719 |
| 24 | 1942966098461 |
| 25 | 7311862919106 |
| 26 | 27582428518833 |
| 27 | 104279585166245 |