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 | 20 |
| 2 | 944 |
| 3 | 49564 |
| 4 | 2753720 |
| 5 | 157871240 |
| 6 | 9233006540 |
| 7 | 547490880980 |
| 8 | 32795094564080 |
| 9 | 1979734520212192 |
| 10 | 120244316085073616 |
| 11 | 7339672750101339356 |
| 12 | 449852213026938118560 |
| 13 | 27666867082225970134160 |