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 | 20 |
| 2 | 324 |
| 3 | 5200 |
| 4 | 83300 |
| 5 | 1333584 |
| 6 | 21344400 |
| 7 | 341580096 |
| 8 | 5466017700 |
| 9 | 87464462800 |
| 10 | 1399525960976 |
| 11 | 22393543798080 |
| 12 | 358310523944464 |
| 13 | 5733141459080000 |
| 14 | 91732470946920000 |
| 15 | 1467748145667974400 |
| 16 | 23484346290765886500 |
| 17 | 375754541311565499600 |
| 18 | 6012139892071344570000 |