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 | 3 |
| 4 | 0 |
| 5 | 22 |
| 6 | 186 |
| 7 | 1603 |
| 8 | 7772 |
| 9 | 47478 |
| 10 | 303278 |
| 11 | 1671273 |
| 12 | 9121582 |
| 13 | 50322028 |
| 14 | 270896326 |
| 15 | 1426536267 |
| 16 | 7454807822 |
| 17 | 38607660199 |
| 18 | 197696949844 |
| 19 | 1003736587788 |
| 20 | 5060326202622 |
| 21 | 25334034892953 |
| 22 | 126024078250318 |
| 23 | 623383415637750 |
| 24 | 3067618264121349 |
| 25 | 15022847233751804 |
| 26 | 73245459228339114 |