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 | 8 |
| 2 | 30 |
| 3 | 126 |
| 4 | 518 |
| 5 | 2138 |
| 6 | 8818 |
| 7 | 36374 |
| 8 | 150038 |
| 9 | 618890 |
| 10 | 2552850 |
| 11 | 10530214 |
| 12 | 43435926 |
| 13 | 179168218 |
| 14 | 739048370 |
| 15 | 3048489846 |
| 16 | 12574671318 |
| 17 | 51869078378 |
| 18 | 213954005138 |
| 19 | 882535756294 |
| 20 | 3640358873558 |
| 21 | 15016063240250 |
| 22 | 61939540321970 |