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 | 7 |
| 2 | 29 |
| 3 | 103 |
| 4 | 417 |
| 5 | 1717 |
| 6 | 7229 |
| 7 | 30793 |
| 8 | 132225 |
| 9 | 570649 |
| 10 | 2470769 |
| 11 | 10719793 |
| 12 | 46569777 |
| 13 | 202477633 |
| 14 | 880792193 |
| 15 | 3832748833 |
| 16 | 16681516545 |
| 17 | 72613292353 |
| 18 | 316105114817 |
| 19 | 1376159456641 |
| 20 | 5991281182977 |
| 21 | 26084303730049 |