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 | 2 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 31 |
| 6 | 127 |
| 7 | 383 |
| 8 | 991 |
| 9 | 2039 |
| 10 | 3583 |
| 11 | 6143 |
| 12 | 8191 |
| 13 | 63487 |
| 14 | 129023 |
| 15 | 131071 |
| 16 | 522239 |
| 17 | 524287 |
| 18 | 1966079 |
| 19 | 4128767 |
| 20 | 14680063 |
| 21 | 33546239 |
| 22 | 67108351 |
| 23 | 201064447 |
| 24 | 260046847 |
| 25 | 536739839 |
| 26 | 1073479679 |
| 27 | 2147483647 |
| 28 | 8581545983 |
| 29 | 16911433727 |