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 | 4 |
| 4 | 53 |
| 5 | 936 |
| 6 | 25325 |
| 7 | 933980 |
| 8 | 45504649 |
| 9 | 2824517520 |
| 10 | 217690037497 |
| 11 | 20394614883316 |
| 12 | 2282650939846781 |
| 13 | 300814135522967736 |
| 14 | 46103574973075123877 |
| 15 | 8130996533576437261772 |
| 16 | 1635028654501420083152785 |
| 17 | 371853339350614571322913824 |
| 18 | 94969025880924845123887493233 |