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 | 4 |
| 3 | 27 |
| 4 | 252 |
| 5 | 2935 |
| 6 | 40330 |
| 7 | 632352 |
| 8 | 11070192 |
| 9 | 213109881 |
| 10 | 4460816992 |
| 11 | 100651469996 |
| 12 | 2431215093846 |
| 13 | 62514061904580 |
| 14 | 1703115911340272 |
| 15 | 48965931282533948 |
| 16 | 1480607510447121328 |
| 17 | 46944740372499336665 |