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 | 0 |
| 3 | 1 |
| 4 | 69 |
| 5 | 1694 |
| 6 | 22932 |
| 7 | 208152 |
| 8 | 1413720 |
| 9 | 7697052 |
| 10 | 35194302 |
| 11 | 139687119 |
| 12 | 493127635 |
| 13 | 1577331756 |
| 14 | 4637757488 |
| 15 | 12679063488 |
| 16 | 32529562560 |
| 17 | 78917794128 |
| 18 | 182184724908 |
| 19 | 402332471541 |
| 20 | 853769650041 |
| 21 | 1747606106554 |
| 22 | 3462012537060 |
| 23 | 6656436729800 |
| 24 | 12452933493000 |