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 | 0 |
| 1 | 1 |
| 2 | 140 |
| 3 | 4995 |
| 4 | 65824 |
| 5 | 489125 |
| 6 | 2521476 |
| 7 | 10092775 |
| 8 | 33562880 |
| 9 | 96870249 |
| 10 | 250025500 |
| 11 | 589527851 |
| 12 | 1290008160 |
| 13 | 2651218765 |
| 14 | 5165397524 |
| 15 | 9611031375 |
| 16 | 17180133376 |
| 17 | 29647326545 |
| 18 | 49590297900 |
| 19 | 80672546899 |
| 20 | 128000804000 |
| 21 | 198571037301 |
| 22 | 301818598180 |
| 23 | 450289780535 |