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 | 7 |
| 1 | 30 |
| 2 | 259 |
| 3 | 3127 |
| 4 | 46657 |
| 5 | 823543 |
| 6 | 16777215 |
| 7 | 37665879 |
| 8 | 77777775 |
| 9 | 150051213 |
| 10 | 273624711 |
| 11 | 475842915 |
| 12 | 794655639 |
| 13 | 1281445305 |
| 14 | 2004318063 |
| 15 | 3051893870 |
| 16 | 4537630813 |
| 17 | 6604718946 |
| 18 | 9431578931 |
| 19 | 13238000758 |
| 20 | 18291957825 |
| 21 | 24917131658 |
| 22 | 33501182551 |
| 23 | 44504801406 |
| 24 | 58471578053 |
| 25 | 76038721330 |