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 | 2 |
| 4 | 17 |
| 5 | 100 |
| 6 | 506 |
| 7 | 2366 |
| 8 | 10556 |
| 9 | 45696 |
| 10 | 193800 |
| 11 | 810084 |
| 12 | 3350479 |
| 13 | 13748020 |
| 14 | 56071470 |
| 15 | 227613750 |
| 16 | 920540040 |
| 17 | 3711935040 |
| 18 | 14932102320 |
| 19 | 59951235420 |
| 20 | 240316859250 |
| 21 | 962056169256 |
| 22 | 3847193657076 |
| 23 | 15370712686252 |
| 24 | 61364157982952 |