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 | 1 |
| 2 | 5 |
| 3 | 45 |
| 4 | 553 |
| 5 | 8525 |
| 6 | 157481 |
| 7 | 3383989 |
| 8 | 82823777 |
| 9 | 2272771305 |
| 10 | 69070483549 |
| 11 | 2301873355661 |
| 12 | 83445967372681 |
| 13 | 3268307044050997 |
| 14 | 137510640882447041 |
| 15 | 6184402325475261525 |
| 16 | 296032663549928711041 |
| 17 | 15025296455500536616337 |