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 | 2 |
| 1 | -1 |
| 2 | -1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 1 |
| 6 | 3 |
| 7 | 9 |
| 8 | 19 |
| 9 | 33 |
| 10 | 67 |
| 11 | 137 |
| 12 | 275 |
| 13 | 545 |
| 14 | 1091 |
| 15 | 2185 |
| 16 | 4371 |
| 17 | 8737 |
| 18 | 17475 |
| 19 | 34953 |
| 20 | 69907 |
| 21 | 139809 |
| 22 | 279619 |
| 23 | 559241 |
| 24 | 1118483 |
| 25 | 2236961 |
| 26 | 4473923 |
| 27 | 8947849 |
| 28 | 17895699 |
| 29 | 35791393 |
| 30 | 71582787 |
| 31 | 143165577 |
| 32 | 286331155 |
| 33 | 572662305 |
| 34 | 1145324611 |
| 35 | 2290649225 |
| 36 | 4581298451 |
| 37 | 9162596897 |