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 | 16 |
| 2 | 240 |
| 3 | 3552 |
| 4 | 52224 |
| 5 | 764672 |
| 6 | 11163936 |
| 7 | 162631712 |
| 8 | 2365037376 |
| 9 | 34344187424 |
| 10 | 498139336992 |
| 11 | 7217820903328 |
| 12 | 104490673015136 |
| 13 | 1511512136496064 |
| 14 | 21849735526096256 |
| 15 | 315654728421607968 |
| 16 | 4557598148470097472 |
| 17 | 65771755517857808768 |
| 18 | 948727279133187672224 |
| 19 | 13679121303056997294080 |
| 20 | 197153311343380929158240 |