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 | 1 |
| 2 | 20 |
| 3 | 285 |
| 4 | 3976 |
| 5 | 55385 |
| 6 | 771420 |
| 7 | 10744501 |
| 8 | 149651600 |
| 9 | 2084377905 |
| 10 | 29031639076 |
| 11 | 404358569165 |
| 12 | 5631988329240 |
| 13 | 78443478040201 |
| 14 | 1092576704233580 |
| 15 | 15217630381229925 |
| 16 | 211954248632985376 |
| 17 | 2952141850480565345 |
| 18 | 41118031658094929460 |
| 19 | 572700301362848447101 |