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 | 7 |
| 4 | 105 |
| 5 | 1418 |
| 6 | 17572 |
| 7 | 207207 |
| 8 | 2367507 |
| 9 | 26483012 |
| 10 | 291646797 |
| 11 | 3173159326 |
| 12 | 34192782745 |
| 13 | 365561221293 |
| 14 | 3882841742380 |
| 15 | 41015564702074 |
| 16 | 431227959019552 |
| 17 | 4515480975731045 |
| 18 | 47115876816676830 |