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 | 24 |
| 3 | 553 |
| 4 | 12720 |
| 5 | 292561 |
| 6 | 6728904 |
| 7 | 154764793 |
| 8 | 3559590240 |
| 9 | 81870575521 |
| 10 | 1883023236984 |
| 11 | 43309534450633 |
| 12 | 996119292364560 |
| 13 | 22910743724384881 |
| 14 | 526947105660852264 |
| 15 | 12119783430199602073 |
| 16 | 278755018894590847680 |
| 17 | 6411365434575589496641 |
| 18 | 147461404995238558422744 |