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 | 7 |
| 2 | 48 |
| 3 | 324 |
| 4 | 2160 |
| 5 | 14256 |
| 6 | 93312 |
| 7 | 606528 |
| 8 | 3919104 |
| 9 | 25194240 |
| 10 | 161243136 |
| 11 | 1027924992 |
| 12 | 6530347008 |
| 13 | 41358864384 |
| 14 | 261213880320 |
| 15 | 1645647446016 |
| 16 | 10344069660672 |
| 17 | 64885527871488 |
| 18 | 406239826673664 |
| 19 | 2538998916710400 |
| 20 | 15843353240272896 |
| 21 | 98716277881700352 |
| 22 | 614234617930579968 |