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 | 19 |
| 2 | 31 |
| 3 | 79 |
| 4 | 271 |
| 5 | 1039 |
| 6 | 4111 |
| 7 | 65551 |
| 8 | 4194319 |
| 9 | 67108879 |
| 10 | 1073741839 |
| 11 | 4294967311 |
| 12 | 1099511627791 |
| 13 | 4398046511119 |
| 14 | 70368744177679 |
| 15 | 4722366482869645213711 |
| 16 | 75557863725914323419151 |