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 | 5 |
| 1 | 11 |
| 2 | 35 |
| 3 | 131 |
| 4 | 515 |
| 5 | 2051 |
| 6 | 8195 |
| 7 | 32771 |
| 8 | 131075 |
| 9 | 524291 |
| 10 | 2097155 |
| 11 | 8388611 |
| 12 | 33554435 |
| 13 | 134217731 |
| 14 | 536870915 |
| 15 | 2147483651 |
| 16 | 8589934595 |
| 17 | 34359738371 |
| 18 | 137438953475 |
| 19 | 549755813891 |
| 20 | 2199023255555 |
| 21 | 8796093022211 |
| 22 | 35184372088835 |
| 23 | 140737488355331 |
| 24 | 562949953421315 |
| 25 | 2251799813685251 |