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 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | 1 |
| 5 | 5 |
| 6 | 19 |
| 7 | 47 |
| 8 | 109 |
| 9 | 233 |
| 10 | 483 |
| 11 | 993 |
| 12 | 2011 |
| 13 | 4055 |
| 14 | 8149 |
| 15 | 16337 |
| 16 | 32715 |
| 17 | 65477 |
| 18 | 131011 |
| 19 | 262077 |
| 20 | 524217 |
| 21 | 1048503 |
| 22 | 2097073 |
| 23 | 4194221 |
| 24 | 8388519 |
| 25 | 16777119 |
| 26 | 33554331 |
| 27 | 67108761 |
| 28 | 134217621 |
| 29 | 268435347 |
| 30 | 536870799 |
| 31 | 1073741697 |
| 32 | 2147483517 |
| 33 | 4294967159 |
| 34 | 8589934453 |
| 35 | 17179869035 |