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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 8 |
| 6 | 12 |
| 7 | 129 |
| 8 | 874 |
| 9 | 9630 |
| 10 | 167001 |
| 11 | 3043147 |
| 12 | 72844510 |
| 13 | 2423789655 |
| 14 | 106665874384 |
| 15 | 6156805673648 |
| 16 | 470151743582651 |
| 17 | 47558937432498729 |
| 18 | 6363358599941131580 |
| 19 | 1126147544855148769425 |
| 20 | 263646401550138303553708 |
| 21 | 81649922556593759124887197 |