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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 16 |
| 5 | 98 |
| 6 | 879 |
| 7 | 11260 |
| 8 | 230505 |
| 9 | 7949596 |
| 10 | 483572280 |
| 11 | 53011686200 |
| 12 | 10589943940654 |
| 13 | 3880959679322754 |
| 14 | 2623201177625659987 |
| 15 | 3286005731275218388682 |
| 16 | 7663042204550840483139108 |
| 17 | 33407704152242477510352455230 |
| 18 | 273327599183687887638526170380380 |