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 | 29 |
| 2 | 139 |
| 3 | 521 |
| 4 | 2287 |
| 5 | 10099 |
| 6 | 45751 |
| 7 | 209763 |
| 8 | 971847 |
| 9 | 4537547 |
| 10 | 21319129 |
| 11 | 100678563 |
| 12 | 477482659 |
| 13 | 2272723391 |
| 14 | 10851284317 |
| 15 | 51949675591 |
| 16 | 249291056151 |
| 17 | 1198762801227 |
| 18 | 5775145319281 |
| 19 | 27868380808227 |
| 20 | 134681613733997 |