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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 9 |
| 7 | 19 |
| 8 | 46 |
| 9 | 110 |
| 10 | 291 |
| 11 | 822 |
| 12 | 2455 |
| 13 | 7740 |
| 14 | 25635 |
| 15 | 88849 |
| 16 | 320749 |
| 17 | 1202674 |
| 18 | 4670156 |
| 19 | 18741145 |
| 20 | 77553119 |
| 21 | 330321299 |
| 22 | 1445829174 |
| 23 | 6493985903 |
| 24 | 29891948760 |
| 25 | 140843699641 |
| 26 | 678576973614 |
| 27 | 3339785593878 |