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 | 20 |
| 2 | 252 |
| 3 | 2860 |
| 4 | 30940 |
| 5 | 325584 |
| 6 | 3364900 |
| 7 | 34337160 |
| 8 | 347103900 |
| 9 | 3483301360 |
| 10 | 34754081648 |
| 11 | 345120260940 |
| 12 | 3413758188932 |
| 13 | 33655718658800 |
| 14 | 330869721936600 |
| 15 | 3244839440755920 |
| 16 | 31754250910172700 |
| 17 | 310165459118369712 |
| 18 | 3024542552887591120 |
| 19 | 29449493278116018800 |
| 20 | 286360607519186119920 |