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 | 45 |
| 2 | 1215 |
| 3 | 25515 |
| 4 | 459270 |
| 5 | 7440174 |
| 6 | 111602610 |
| 7 | 1578379770 |
| 8 | 21308126895 |
| 9 | 277005649635 |
| 10 | 3490271185401 |
| 11 | 42835146366285 |
| 12 | 514021756395420 |
| 13 | 6049640671423020 |
| 14 | 70002984912180660 |
| 15 | 798034027998859524 |
| 16 | 8977882814987169645 |
| 17 | 99812932472504415465 |
| 18 | 1097942257197548570115 |