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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 76 |
| 6 | 734 |
| 7 | 7414 |
| 8 | 71986 |
| 9 | 638499 |
| 10 | 5558790 |
| 11 | 47971603 |
| 12 | 410502410 |
| 13 | 3473846885 |
| 14 | 29078659564 |
| 15 | 241699322196 |
| 16 | 1997778940804 |
| 17 | 16429720592636 |
| 18 | 134489816829048 |
| 19 | 1096404231410945 |
| 20 | 8906880161717904 |
| 21 | 72131791267258552 |
| 22 | 582512418898356698 |
| 23 | 4692186192041626600 |