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 | 20 |
| 2 | 72 |
| 3 | 1824 |
| 4 | 4224 |
| 5 | 116736 |
| 6 | 270336 |
| 7 | 7471104 |
| 8 | 520617984 |
| 9 | 1082130432 |
| 10 | 133680857088 |
| 11 | 1926292832256 |
| 12 | 4535485464576 |
| 13 | 125344325566464 |
| 14 | 8734520371052544 |
| 15 | 558587091282296832 |
| 16 | 1161928703861587968 |
| 17 | 143538727323552448512 |
| 18 | 2068341179264683474944 |
| 19 | 4869940435459321626624 |