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 | 8 |
| 4 | 31 |
| 5 | 119 |
| 6 | 456 |
| 7 | 1749 |
| 8 | 6721 |
| 9 | 25883 |
| 10 | 99892 |
| 11 | 386308 |
| 12 | 1496782 |
| 13 | 5809478 |
| 14 | 22584160 |
| 15 | 87922215 |
| 16 | 342741285 |
| 17 | 1337698515 |
| 18 | 5226732060 |
| 19 | 20442936360 |
| 20 | 80031775890 |
| 21 | 313585934610 |
| 22 | 1229695855440 |
| 23 | 4825705232010 |
| 24 | 18950613058026 |
| 25 | 74467158658974 |
| 26 | 292797216620776 |
| 27 | 1151895428382104 |