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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 18 |
| 5 | 295 |
| 6 | 5115 |
| 7 | 96838 |
| 8 | 2012724 |
| 9 | 45825148 |
| 10 | 1137703140 |
| 11 | 30643915984 |
| 12 | 891001127016 |
| 13 | 27835772321344 |
| 14 | 930387252759328 |
| 15 | 33141746095999552 |
| 16 | 1253756533365348992 |
| 17 | 50210676392866266880 |
| 18 | 2122613151692627299584 |
| 19 | 94470824166941637093376 |