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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 16 |
| 6 | 80 |
| 7 | 436 |
| 8 | 2786 |
| 9 | 19538 |
| 10 | 147771 |
| 11 | 1182095 |
| 12 | 9890463 |
| 13 | 85866068 |
| 14 | 769212600 |
| 15 | 7080642324 |
| 16 | 66754295740 |
| 17 | 642857161008 |
| 18 | 6309892895338 |
| 19 | 6300760829973 |
| 20 | 639049976047882 |
| 21 | 6574281878157350 |
| 22 | 68519019810831408 |
| 23 | 722711344283052608 |
| 24 | 7707346411412142258 |
| 25 | 83037096707432139882 |