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 | 1 |
| 5 | 6 |
| 6 | 37 |
| 7 | 183 |
| 8 | 877 |
| 9 | 3930 |
| 10 | 17185 |
| 11 | 73095 |
| 12 | 306361 |
| 13 | 1267266 |
| 14 | 5198557 |
| 15 | 21182343 |
| 16 | 85910917 |
| 17 | 347187210 |
| 18 | 1399451545 |
| 19 | 5629911015 |
| 20 | 22616256721 |
| 21 | 90754855026 |
| 22 | 363890126677 |
| 23 | 1458172596903 |
| 24 | 5840531635357 |
| 25 | 23385650196090 |