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 | 1 |
| 3 | 8 |
| 4 | 40 |
| 5 | 164 |
| 6 | 601 |
| 7 | 2048 |
| 8 | 6632 |
| 9 | 20680 |
| 10 | 62633 |
| 11 | 185352 |
| 12 | 538272 |
| 13 | 1538892 |
| 14 | 4341905 |
| 15 | 12112960 |
| 16 | 33464240 |
| 17 | 91666192 |
| 18 | 249215921 |
| 19 | 673049800 |
| 20 | 1806888568 |
| 21 | 4824913652 |
| 22 | 12821690281 |
| 23 | 33922774464 |
| 24 | 89391291480 |
| 25 | 234694621656 |
| 26 | 614106591769 |
| 27 | 1601882815304 |
| 28 | 4166439039664 |