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 | 6 |
| 4 | 29 |
| 5 | 510 |
| 6 | 5032 |
| 7 | 161406 |
| 8 | 3294405 |
| 9 | 194342910 |
| 10 | 7934652356 |
| 11 | 881008805886 |
| 12 | 71275547085536 |
| 13 | 15178191426486270 |
| 14 | 2434250064518832302 |
| 15 | 1008694542117649154046 |
| 16 | 321680912414994434144165 |
| 17 | 262063364967549826752315390 |
| 18 | 166681427053102507699172431372 |