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 | 1 |
| 3 | 27 |
| 4 | 486 |
| 5 | 7290 |
| 6 | 98415 |
| 7 | 1240029 |
| 8 | 14880348 |
| 9 | 172186884 |
| 10 | 1937102445 |
| 11 | 21308126895 |
| 12 | 230127770466 |
| 13 | 2447722649502 |
| 14 | 25701087819771 |
| 15 | 266895911974545 |
| 16 | 2745215094595320 |
| 17 | 28001193964872264 |
| 18 | 283512088894331673 |