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 | 0 |
| 4 | 0 |
| 5 | 2578 |
| 6 | 1247116 |
| 7 | 97284860 |
| 8 | 2817340064 |
| 9 | 44218721793 |
| 10 | 457851259868 |
| 11 | 3506596268191 |
| 12 | 21355746900992 |
| 13 | 108582220087480 |
| 14 | 477032549147428 |
| 15 | 1857084405493128 |
| 16 | 6529640029479296 |
| 17 | 21044674478336823 |
| 18 | 62903854631232636 |
| 19 | 176034055470126073 |
| 20 | 464793685059669728 |