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 | 1 |
| 1 | 5 |
| 2 | 22 |
| 3 | 89 |
| 4 | 340 |
| 5 | 1247 |
| 6 | 4438 |
| 7 | 15437 |
| 8 | 52744 |
| 9 | 177659 |
| 10 | 591514 |
| 11 | 1950665 |
| 12 | 6381388 |
| 13 | 20734391 |
| 14 | 66977950 |
| 15 | 215266373 |
| 16 | 688813072 |
| 17 | 2195513843 |
| 18 | 6973830946 |
| 19 | 22083492161 |
| 20 | 69736736596 |
| 21 | 219669514415 |
| 22 | 690387505702 |
| 23 | 2165301501629 |