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 | 5 |
| 2 | 251 |
| 3 | 499 |
| 4 | 751 |
| 5 | 1249 |
| 6 | 4999 |
| 7 | 8089 |
| 8 | 18229 |
| 9 | 31249 |
| 10 | 49999 |
| 11 | 281249 |
| 12 | 4218751 |
| 13 | 4999999 |
| 14 | 9590417 |
| 15 | 31622777 |
| 16 | 68171507 |
| 17 | 74218751 |
| 18 | 574218751 |
| 19 | 5740883989 |
| 20 | 8829261293 |