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 | 22 |
| 3 | 680 |
| 4 | 24074 |
| 5 | 917414 |
| 6 | 36618492 |
| 7 | 1508943612 |
| 8 | 63643109727 |
| 9 | 2732349490669 |
| 10 | 118957846271104 |
| 11 | 5237911268468572 |
| 12 | 232794783971436296 |
| 13 | 10427673857731312064 |
| 14 | 470213556090357498728 |
| 15 | 21325335129901497816528 |