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 | 240 |
| 3 | 5200 |
| 4 | 39200 |
| 5 | 590480 |
| 6 | 1608880 |
| 7 | 8045760 |
| 8 | 15681840 |
| 9 | 49345120 |
| 10 | 198274160 |
| 11 | 295834240 |
| 12 | 855241680 |
| 13 | 1583367520 |
| 14 | 2107120400 |
| 15 | 3593071040 |
| 16 | 7388119440 |
| 17 | 14060176720 |
| 18 | 17173456880 |
| 19 | 30152792560 |
| 20 | 42700092960 |
| 21 | 50444740320 |