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 | 1 |
| 2 | 3 |
| 3 | 22 |
| 4 | 269 |
| 5 | 4606 |
| 6 | 101407 |
| 7 | 2728818 |
| 8 | 86783769 |
| 9 | 3184595686 |
| 10 | 132443395091 |
| 11 | 6156200036746 |
| 12 | 316272966462565 |
| 13 | 17795937622944846 |
| 14 | 1088410048965734055 |
| 15 | 71893314170319604066 |
| 16 | 5100574859506418167601 |
| 17 | 386824334429004242804086 |
| 18 | 31229208329663841200670619 |