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 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 24 |
| 6 | 193 |
| 7 | 2420 |
| 8 | 47912 |
| 9 | 1600524 |
| 10 | 93253226 |
| 11 | 9694177479 |
| 12 | 1822463625183 |
| 13 | 625829508087155 |
| 14 | 395785845695978077 |
| 15 | 464137111800208818956 |
| 16 | 1015091598240432264958267 |
| 17 | 4160447480034069826186309689 |
| 18 | 32088552194861245127627790541334 |