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 | 5 |
| 3 | 30 |
| 4 | 160 |
| 5 | 850 |
| 6 | 4520 |
| 7 | 24040 |
| 8 | 127860 |
| 9 | 680040 |
| 10 | 3616880 |
| 11 | 19236840 |
| 12 | 102313600 |
| 13 | 544168000 |
| 14 | 2894227280 |
| 15 | 15393318880 |
| 16 | 81871340160 |
| 17 | 435443220000 |
| 18 | 2315960597120 |
| 19 | 12317733383040 |
| 20 | 65513444349760 |
| 21 | 348441653760640 |
| 22 | 1853231611930880 |
| 23 | 9856649945242240 |
| 24 | 52423856531251200 |