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 | 1 |
| 5 | 6 |
| 6 | 26 |
| 7 | 97 |
| 8 | 331 |
| 9 | 1064 |
| 10 | 3277 |
| 11 | 9775 |
| 12 | 28448 |
| 13 | 81201 |
| 14 | 228211 |
| 15 | 633384 |
| 16 | 1740037 |
| 17 | 4740327 |
| 18 | 12825008 |
| 19 | 34500649 |
| 20 | 92372683 |
| 21 | 246352952 |
| 22 | 654878173 |
| 23 | 1736172895 |
| 24 | 4592568896 |
| 25 | 12125944161 |
| 26 | 31967715811 |
| 27 | 84170419272 |
| 28 | 221388694261 |
| 29 | 581807602839 |
| 30 | 1527909651152 |
| 31 | 4010192518105 |