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 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 63 |
| 4 | 7206 |
| 5 | 1357300 |
| 6 | 384271700 |
| 7 | 153027592116 |
| 8 | 81648987014364 |
| 9 | 56259916067074896 |
| 10 | 48646018448463951450 |
| 11 | 51584263505394472459750 |
| 12 | 65833976467770842558152992 |
| 13 | 99553004175105699906002335098 |
| 14 | 176031670802373999913671973955080 |
| 15 | 359870756416991348769957239299854000 |