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 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 3 |
| 8 | 20 |
| 9 | 198 |
| 10 | 1390 |
| 11 | 9474 |
| 12 | 35488 |
| 13 | 178448 |
| 14 | 696371 |
| 15 | 2721544 |
| 16 | 10683110 |
| 17 | 41334494 |
| 18 | 155723774 |
| 19 | 596182769 |
| 20 | 2257379379 |
| 21 | 8587521496 |
| 22 | 32688629235 |
| 23 | 124568505590 |
| 24 | 475147925759 |
| 25 | 1815832051949 |