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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 12 |
| 7 | 78 |
| 8 | 364 |
| 9 | 1365 |
| 10 | 4368 |
| 11 | 12377 |
| 12 | 31848 |
| 13 | 75882 |
| 14 | 170560 |
| 15 | 370266 |
| 16 | 803712 |
| 17 | 1827099 |
| 18 | 4531980 |
| 19 | 12346791 |
| 20 | 35783396 |
| 21 | 105681186 |
| 22 | 308229948 |
| 23 | 873545479 |
| 24 | 2392395276 |
| 25 | 6336768804 |
| 26 | 16309261148 |
| 27 | 41095234896 |
| 28 | 102361858716 |
| 29 | 254804224832 |
| 30 | 640481466012 |