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 | 5 |
| 1 | 20 |
| 2 | 120 |
| 3 | 840 |
| 4 | 8400 |
| 5 | 117600 |
| 6 | 2469600 |
| 7 | 79027200 |
| 8 | 3951360000 |
| 9 | 312157440000 |
| 10 | 39331837440000 |
| 11 | 7945031162880000 |
| 12 | 2582135127936000000 |
| 13 | 1353038807038464000000 |
| 14 | 1144670830754540544000000 |
| 15 | 1564765025641456923648000000 |
| 16 | 3458130706667619801262080000000 |