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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 44 |
| 6 | 120 |
| 7 | 328 |
| 8 | 896 |
| 9 | 2448 |
| 10 | 6688 |
| 11 | 18272 |
| 12 | 49920 |
| 13 | 136384 |
| 14 | 372608 |
| 15 | 1017984 |
| 16 | 2781184 |
| 17 | 7598336 |
| 18 | 20759040 |
| 19 | 56714752 |
| 20 | 154947584 |
| 21 | 423324672 |
| 22 | 1156544512 |
| 23 | 3159738368 |
| 24 | 8632565760 |
| 25 | 23584608256 |
| 26 | 64434348032 |
| 27 | 176037912576 |
| 28 | 480944521216 |
| 29 | 1313964867584 |