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 | 24 |
| 3 | 140 |
| 4 | 2319 |
| 5 | 21272 |
| 6 | 262191 |
| 7 | 2746048 |
| 8 | 31411948 |
| 9 | 342302244 |
| 10 | 3830482893 |
| 11 | 42241878920 |
| 12 | 469601959777 |
| 13 | 5197411955932 |
| 14 | 57664560160890 |
| 15 | 638914582091712 |
| 16 | 7084373947760105 |
| 17 | 78520055192688696 |
| 18 | 870480364546718647 |
| 19 | 9649003719594586976 |
| 20 | 106963676725852631636 |