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 | 1 |
| 3 | 4 |
| 4 | 15 |
| 5 | 59 |
| 6 | 250 |
| 7 | 1145 |
| 8 | 5649 |
| 9 | 29874 |
| 10 | 168509 |
| 11 | 1009215 |
| 12 | 6391484 |
| 13 | 42648083 |
| 14 | 298865333 |
| 15 | 2193219124 |
| 16 | 16811408659 |
| 17 | 134289313167 |
| 18 | 1115559002906 |
| 19 | 9619253991637 |
| 20 | 85950089855573 |
| 21 | 794567157607386 |
| 22 | 7588822028424393 |
| 23 | 74783864494826723 |
| 24 | 759461721024357540 |