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 | 0 |
| 4 | 90 |
| 5 | 1716 |
| 6 | 11350 |
| 7 | 49860 |
| 8 | 173745 |
| 9 | 519345 |
| 10 | 1389078 |
| 11 | 3411060 |
| 12 | 7821950 |
| 13 | 16949910 |
| 14 | 35013240 |
| 15 | 69404416 |
| 16 | 132703770 |
| 17 | 245767890 |
| 18 | 442372300 |
| 19 | 776064960 |
| 20 | 1330117230 |
| 21 | 2231754820 |
| 22 | 3672227850 |
| 23 | 5934754020 |
| 24 | 9432962515 |
| 25 | 14763202395 |