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 | 1 |
| 4 | 5 |
| 5 | 19 |
| 6 | 64 |
| 7 | 201 |
| 8 | 603 |
| 9 | 1752 |
| 10 | 4973 |
| 11 | 13871 |
| 12 | 38176 |
| 13 | 103985 |
| 14 | 280947 |
| 15 | 754216 |
| 16 | 2014469 |
| 17 | 5358823 |
| 18 | 14209456 |
| 19 | 37580841 |
| 20 | 99188427 |
| 21 | 261360696 |
| 22 | 687777245 |
| 23 | 1808000351 |
| 24 | 4748806720 |
| 25 | 12464634209 |
| 26 | 32699621859 |
| 27 | 85747477576 |
| 28 | 224777691893 |
| 29 | 589072137367 |
| 30 | 1543445353168 |