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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 24 |
| 5 | 81 |
| 6 | 274 |
| 7 | 927 |
| 8 | 3136 |
| 9 | 10609 |
| 10 | 35890 |
| 11 | 121415 |
| 12 | 410744 |
| 13 | 1389537 |
| 14 | 4700770 |
| 15 | 15902591 |
| 16 | 53798080 |
| 17 | 181997601 |
| 18 | 615693474 |
| 19 | 2082876103 |
| 20 | 7046319384 |
| 21 | 23837527729 |
| 22 | 80641778674 |
| 23 | 272809183135 |
| 24 | 922906855808 |
| 25 | 3122171529233 |