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 | 1 |
| 2 | 3 |
| 3 | 24 |
| 4 | 181 |
| 5 | 1893 |
| 6 | 20601 |
| 7 | 245176 |
| 8 | 3018669 |
| 9 | 38198478 |
| 10 | 493218343 |
| 11 | 6441378129 |
| 12 | 84807054552 |
| 13 | 1120545910725 |
| 14 | 14820493111536 |
| 15 | 195812569428897 |
| 16 | 2580287366558579 |
| 17 | 33878771120862777 |
| 18 | 443012040333754728 |
| 19 | 5770422757461475027 |
| 20 | 74931929672784252306 |