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 | 1 |
| 2 | 68 |
| 3 | 1314 |
| 4 | 18080 |
| 5 | 197350 |
| 6 | 1836792 |
| 7 | 15233316 |
| 8 | 115776768 |
| 9 | 821760390 |
| 10 | 5520171800 |
| 11 | 35438827996 |
| 12 | 219038609088 |
| 13 | 1310833221724 |
| 14 | 7629754810160 |
| 15 | 43348888067400 |
| 16 | 241117582878720 |
| 17 | 1316197491501510 |
| 18 | 7065439665315480 |
| 19 | 37362065079691500 |
| 20 | 194909773207512000 |
| 21 | 1004374157379474420 |