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 | 0 |
| 2 | 48 |
| 3 | 288 |
| 4 | 1680 |
| 5 | 9792 |
| 6 | 57072 |
| 7 | 332640 |
| 8 | 1938768 |
| 9 | 11299968 |
| 10 | 65861040 |
| 11 | 383866272 |
| 12 | 2237336592 |
| 13 | 13040153280 |
| 14 | 76003583088 |
| 15 | 442981345248 |
| 16 | 2581884488400 |
| 17 | 15048325585152 |
| 18 | 87708069022512 |
| 19 | 511200088549920 |
| 20 | 2979492462277008 |
| 21 | 17365754685112128 |
| 22 | 101215035648395760 |