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 | 39 |
| 3 | 159 |
| 4 | 15720 |
| 5 | 63480 |
| 6 | 6256719 |
| 7 | 25265079 |
| 8 | 2490158640 |
| 9 | 10055438160 |
| 10 | 991076882199 |
| 11 | 4002039122799 |
| 12 | 394446108956760 |
| 13 | 1592801515436040 |
| 14 | 156988560287908479 |
| 15 | 633931001104421319 |
| 16 | 62481052548478618080 |
| 17 | 252302945638044249120 |
| 18 | 24867301925734202087559 |