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 | 40 |
| 2 | 880 |
| 3 | 14080 |
| 4 | 183040 |
| 5 | 2050048 |
| 6 | 20500480 |
| 7 | 187432960 |
| 8 | 1593180160 |
| 9 | 12745441280 |
| 10 | 96865353728 |
| 11 | 704475299840 |
| 12 | 4931327098880 |
| 13 | 33381291130880 |
| 14 | 219362770288640 |
| 15 | 1403921729847296 |
| 16 | 8774510811545600 |
| 17 | 53679360258867200 |
| 18 | 322076161553203200 |
| 19 | 1898554215471513600 |