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 | 6 |
| 2 | 57 |
| 3 | 524 |
| 4 | 4803 |
| 5 | 44022 |
| 6 | 403495 |
| 7 | 3698352 |
| 8 | 33898338 |
| 9 | 310705224 |
| 10 | 2847860436 |
| 11 | 26102905368 |
| 12 | 239253883390 |
| 13 | 2192952083712 |
| 14 | 20100149570496 |
| 15 | 184233853423936 |
| 16 | 1688649759962676 |
| 17 | 15477817777932456 |
| 18 | 141866507103389516 |
| 19 | 1300319342589168000 |
| 20 | 11918460722228694720 |