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) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 66 |
| 4 | 528 |
| 5 | 1232 |
| 6 | 16016 |
| 7 | 496496 |
| 8 | 4468464 |
| 9 | 183207024 |
| 10 | 4213761552 |
| 11 | 71633946384 |
| 12 | 71633946384 |
| 13 | 4369670729424 |
| 14 | 4369670729424 |
| 15 | 310246621789104 |
| 16 | 5894685813992976 |
| 17 | 53052172325936784 |
| 18 | 2281243410015281712 |