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) |
|---|---|
| 4 | 4 |
| 5 | 16 |
| 6 | 91 |
| 7 | 631 |
| 8 | 5041 |
| 9 | 45361 |
| 10 | 453601 |
| 11 | 4989601 |
| 12 | 59875201 |
| 13 | 778377601 |
| 14 | 10897286401 |
| 15 | 163459296001 |
| 16 | 2615348736001 |
| 17 | 44460928512001 |
| 18 | 800296713216001 |
| 19 | 15205637551104001 |
| 20 | 304112751022080001 |
| 21 | 6386367771463680001 |