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 | 1 |
| 2 | 20 |
| 3 | 1170 |
| 4 | 136000 |
| 5 | 26276900 |
| 6 | 7605187200 |
| 7 | 3079172005000 |
| 8 | 1661435709440000 |
| 9 | 1152219238256970000 |
| 10 | 998612074565747200000 |
| 11 | 1057635292751424744500000 |
| 12 | 1344007509419503558656000000 |
| 13 | 2018255243962112126438545000000 |