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 | 15 |
| 2 | 179 |
| 3 | 2070 |
| 4 | 24574 |
| 5 | 305956 |
| 6 | 4028156 |
| 7 | 56231712 |
| 8 | 832391136 |
| 9 | 13051234944 |
| 10 | 216374987520 |
| 11 | 3785626465920 |
| 12 | 69751622298240 |
| 13 | 1350747863435520 |
| 14 | 27437426560500480 |
| 15 | 583506719443584000 |
| 16 | 12969079056388224000 |
| 17 | 300749419818102528000 |
| 18 | 7265204785551331584000 |