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 | 8 |
| 4 | 0 |
| 5 | 82 |
| 6 | 744 |
| 7 | 6378 |
| 8 | 31088 |
| 9 | 189688 |
| 10 | 1213112 |
| 11 | 6683852 |
| 12 | 36486328 |
| 13 | 201282470 |
| 14 | 1083585304 |
| 15 | 5706117458 |
| 16 | 29819231288 |
| 17 | 154430502724 |
| 18 | 790787799376 |
| 19 | 4014945695196 |
| 20 | 20241304810488 |
| 21 | 101336136490228 |
| 22 | 504096313001272 |
| 23 | 2493533648002492 |
| 24 | 12270473056485396 |