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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 15 |
| 5 | 92 |
| 6 | 757 |
| 7 | 8899 |
| 8 | 125261 |
| 9 | 2232782 |
| 10 | 51902553 |
| 11 | 1327191561 |
| 12 | 41351244491 |
| 13 | 1452937916515 |
| 14 | 54332144724834 |
| 15 | 2246960940148460 |
| 16 | 105818707666943651 |
| 17 | 5595105626396158784 |
| 18 | 308241771351984486729 |
| 19 | 18772520681296116861073 |