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 | 4 |
| 2 | 16 |
| 3 | 62 |
| 4 | 235 |
| 5 | 888 |
| 6 | 3349 |
| 7 | 12620 |
| 8 | 47545 |
| 9 | 179104 |
| 10 | 674666 |
| 11 | 2541362 |
| 12 | 9572864 |
| 13 | 36059224 |
| 14 | 135828387 |
| 15 | 511640114 |
| 16 | 1927252354 |
| 17 | 7259597884 |
| 18 | 27345542237 |
| 19 | 103005522894 |
| 20 | 388002462425 |
| 21 | 1461532415920 |
| 22 | 5505318159061 |
| 23 | 20737499694808 |
| 24 | 78114267177504 |