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 | 3 |
| 3 | 14 |
| 4 | 84 |
| 5 | 594 |
| 6 | 4719 |
| 7 | 40898 |
| 8 | 379236 |
| 9 | 3711916 |
| 10 | 37975756 |
| 11 | 403127256 |
| 12 | 4415203280 |
| 13 | 49671036900 |
| 14 | 571947380775 |
| 15 | 6721316278650 |
| 16 | 80419959684900 |
| 17 | 977737404590100 |
| 18 | 12058761323277900 |
| 19 | 150656212896017400 |
| 20 | 1904342169333848400 |
| 21 | 24328661192286773400 |
| 22 | 313839729380499376860 |