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 | 0 |
| 3 | 26208 |
| 4 | 530712 |
| 5 | 6368544 |
| 6 | 47331648 |
| 7 | 256864608 |
| 8 | 1116087336 |
| 9 | 4092877152 |
| 10 | 12996075456 |
| 11 | 37058557536 |
| 12 | 96952754808 |
| 13 | 232778774592 |
| 14 | 526258264896 |
| 15 | 1128148021728 |
| 16 | 2286143305992 |
| 17 | 4451523096384 |
| 18 | 8386247967552 |
| 19 | 15130902687264 |
| 20 | 26614339616592 |
| 21 | 45684687301344 |