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) |
|---|---|
| 1 | 0 |
| 2 | 54 |
| 3 | 648 |
| 4 | 4860 |
| 5 | 29160 |
| 6 | 153090 |
| 7 | 734832 |
| 8 | 3306744 |
| 9 | 14171760 |
| 10 | 58458510 |
| 11 | 233834040 |
| 12 | 911952756 |
| 13 | 3482001432 |
| 14 | 13057505370 |
| 15 | 48212327520 |
| 16 | 175630621680 |
| 17 | 632270238048 |
| 18 | 2252462723046 |
| 19 | 7949868434280 |
| 20 | 27824539519980 |
| 21 | 96653663595720 |
| 22 | 333455139405234 |
| 23 | 1143274763675088 |