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 | 0 |
| 3 | 18 |
| 4 | 312 |
| 5 | 2340 |
| 6 | 11160 |
| 7 | 39990 |
| 8 | 117648 |
| 9 | 299592 |
| 10 | 683280 |
| 11 | 1428570 |
| 12 | 2783880 |
| 13 | 5118828 |
| 14 | 8964072 |
| 15 | 15059070 |
| 16 | 24408480 |
| 17 | 38347920 |
| 18 | 58619808 |
| 19 | 87460002 |
| 20 | 127695960 |
| 21 | 182857140 |
| 22 | 257298360 |
| 23 | 356336838 |
| 24 | 486403632 |
| 25 | 655210200 |
| 26 | 871930800 |
| 27 | 1147401450 |