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 | 1 |
| 2 | 1 |
| 3 | 6 |
| 4 | 60 |
| 5 | 790 |
| 6 | 12488 |
| 7 | 226176 |
| 8 | 4567245 |
| 9 | 101057170 |
| 10 | 2421311002 |
| 11 | 62292579316 |
| 12 | 1709994461396 |
| 13 | 49844902545256 |
| 14 | 1536870296603860 |
| 15 | 49965056185462360 |
| 16 | 1708221871912841430 |
| 17 | 61272046476315041664 |
| 18 | 2301058164207089144028 |
| 19 | 90309756129843950212480 |
| 20 | 3697832634432220792202296 |