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 | 1 |
| 1 | 56 |
| 2 | 1463 |
| 3 | 24320 |
| 4 | 293930 |
| 5 | 2785552 |
| 6 | 21737254 |
| 7 | 144538624 |
| 8 | 839848450 |
| 9 | 4347450800 |
| 10 | 20355385710 |
| 11 | 87265194240 |
| 12 | 345992859975 |
| 13 | 1279301331000 |
| 14 | 4442249264625 |
| 15 | 14573017267200 |
| 16 | 45398364338250 |
| 17 | 134897996890800 |
| 18 | 383822534859750 |
| 19 | 1049290591104000 |
| 20 | 2764459117589400 |