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 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 6 |
| 5 | 10 |
| 6 | 0 |
| 7 | 0 |
| 8 | 504 |
| 9 | 2656 |
| 10 | 0 |
| 11 | 0 |
| 12 | 455936 |
| 13 | 3040560 |
| 14 | 0 |
| 15 | 0 |
| 16 | 1400156768 |
| 17 | 12248982496 |
| 18 | 0 |
| 19 | 0 |
| 20 | 11435578798976 |
| 21 | 123564928167168 |
| 22 | 0 |
| 23 | 0 |
| 24 | 204776117691241344 |
| 25 | 2634563519776965376 |
| 26 | 0 |
| 27 | 0 |
| 28 | 7064747252076429464064 |
| 29 | 105435171495207196553472 |
| 30 | 0 |
| 31 | 0 |