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 | 15 |
| 2 | 32767 |
| 3 | 7174453 |
| 4 | 357913941 |
| 5 | 7629394531 |
| 6 | 94036996915 |
| 7 | 791260251657 |
| 8 | 5026338869833 |
| 9 | 25736391511831 |
| 10 | 111111111111111 |
| 11 | 417724816941565 |
| 12 | 1400638324962397 |
| 13 | 4265491084507563 |
| 14 | 11966776581370171 |
| 15 | 31278135027204241 |
| 16 | 76861433640456465 |
| 17 | 178901440719363487 |