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 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 34 |
| 4 | 138 |
| 5 | 492 |
| 6 | 1830 |
| 7 | 6804 |
| 8 | 25576 |
| 9 | 96728 |
| 10 | 367932 |
| 11 | 1405884 |
| 12 | 5392590 |
| 13 | 20751504 |
| 14 | 80076872 |
| 15 | 309748096 |
| 16 | 1200669828 |
| 17 | 4662772672 |
| 18 | 18137643524 |
| 19 | 70657441212 |
| 20 | 275620281310 |
| 21 | 1076429623256 |
| 22 | 4208562777342 |
| 23 | 16470788108008 |
| 24 | 64519534566362 |
| 25 | 252948764993472 |
| 26 | 992453764928050 |