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 | 16 |
| 2 | 165 |
| 3 | 1400 |
| 4 | 10661 |
| 5 | 75936 |
| 6 | 517524 |
| 7 | 3420960 |
| 8 | 22123530 |
| 9 | 140782048 |
| 10 | 885008839 |
| 11 | 5511579528 |
| 12 | 34073731965 |
| 13 | 209428887360 |
| 14 | 1281220578936 |
| 15 | 7808422173120 |
| 16 | 47440778110398 |
| 17 | 287490594872160 |
| 18 | 1738463164498410 |
| 19 | 10493677382085744 |
| 20 | 63245915436539682 |
| 21 | 380697445274657984 |