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 | 7 |
| 2 | 22 |
| 3 | 73 |
| 4 | 268 |
| 5 | 1039 |
| 6 | 4114 |
| 7 | 16405 |
| 8 | 65560 |
| 9 | 262171 |
| 10 | 1048606 |
| 11 | 4194337 |
| 12 | 16777252 |
| 13 | 67108903 |
| 14 | 268435498 |
| 15 | 1073741869 |
| 16 | 4294967344 |
| 17 | 17179869235 |
| 18 | 68719476790 |
| 19 | 274877907001 |
| 20 | 1099511627836 |
| 21 | 4398046511167 |
| 22 | 17592186044482 |
| 23 | 70368744177733 |
| 24 | 281474976710728 |
| 25 | 1125899906842699 |