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 | 1 |
| 2 | 7 |
| 3 | 25 |
| 4 | 127 |
| 5 | 449 |
| 6 | 2279 |
| 7 | 8057 |
| 8 | 40895 |
| 9 | 144577 |
| 10 | 733831 |
| 11 | 2594329 |
| 12 | 13168063 |
| 13 | 46553345 |
| 14 | 236291303 |
| 15 | 835365881 |
| 16 | 4240075391 |
| 17 | 14990032513 |
| 18 | 76085065735 |
| 19 | 268985219353 |
| 20 | 1365291107839 |
| 21 | 4826743915841 |
| 22 | 24499154875367 |
| 23 | 86612405265785 |
| 24 | 439619496648767 |
| 25 | 1554196550868289 |