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 | 12 |
| 2 | 126 |
| 3 | 1260 |
| 4 | 12285 |
| 5 | 117936 |
| 6 | 1120392 |
| 7 | 10563696 |
| 8 | 99034650 |
| 9 | 924323400 |
| 10 | 8596207620 |
| 11 | 79710288840 |
| 12 | 737320171770 |
| 13 | 6806032354800 |
| 14 | 62712726697800 |
| 15 | 576957085619760 |
| 16 | 5300793224131545 |
| 17 | 48642573115560060 |
| 18 | 445890253559300550 |
| 19 | 4083416006279910300 |
| 20 | 37363256457461179245 |
| 21 | 341606916182502210240 |