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 | 6 |
| 3 | 12 |
| 4 | 22 |
| 5 | 40 |
| 6 | 74 |
| 7 | 140 |
| 8 | 270 |
| 9 | 528 |
| 10 | 1042 |
| 11 | 2068 |
| 12 | 4118 |
| 13 | 8216 |
| 14 | 16410 |
| 15 | 32796 |
| 16 | 65566 |
| 17 | 131104 |
| 18 | 262178 |
| 19 | 524324 |
| 20 | 1048614 |
| 21 | 2097192 |
| 22 | 4194346 |
| 23 | 8388652 |
| 24 | 16777262 |
| 25 | 33554480 |
| 26 | 67108914 |
| 27 | 134217780 |
| 28 | 268435510 |
| 29 | 536870968 |
| 30 | 1073741882 |
| 31 | 2147483708 |