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 | 65 |
| 2 | 2080 |
| 3 | 43680 |
| 4 | 677040 |
| 5 | 8259888 |
| 6 | 82598880 |
| 7 | 696190560 |
| 8 | 5047381560 |
| 9 | 31966749880 |
| 10 | 179013799328 |
| 11 | 895068996640 |
| 12 | 4027810484880 |
| 13 | 16421073515280 |
| 14 | 60992558771040 |
| 15 | 207374699821536 |
| 16 | 648045936942300 |
| 17 | 1867897112363100 |
| 18 | 4981058966301600 |
| 19 | 12321566916640800 |