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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 19 |
| 5 | 124 |
| 6 | 1069 |
| 7 | 11464 |
| 8 | 146599 |
| 9 | 2173624 |
| 10 | 36633049 |
| 11 | 691362124 |
| 12 | 14440672699 |
| 13 | 330674815924 |
| 14 | 8236528396549 |
| 15 | 221694575073424 |
| 16 | 6411977928702799 |
| 17 | 198310761891213424 |
| 18 | 6530970632654064049 |
| 19 | 228174066109353835924 |