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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1974 |
| 6 | 42368 |
| 7 | 397014 |
| 8 | 2326320 |
| 9 | 10087628 |
| 10 | 35464464 |
| 11 | 106783320 |
| 12 | 285336128 |
| 13 | 693331146 |
| 14 | 1558986816 |
| 15 | 3286192514 |
| 16 | 6558317232 |
| 17 | 12488282352 |
| 18 | 22829958032 |
| 19 | 40269324564 |
| 20 | 68817690624 |
| 21 | 114333609854 |
| 22 | 185205015936 |