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 | 7 |
| 2 | 23 |
| 3 | 79 |
| 4 | 287 |
| 5 | 1087 |
| 6 | 4223 |
| 7 | 16639 |
| 8 | 66047 |
| 9 | 263167 |
| 10 | 1050623 |
| 11 | 4198399 |
| 12 | 16785407 |
| 13 | 67125247 |
| 14 | 268468223 |
| 15 | 1073807359 |
| 16 | 4295098367 |
| 17 | 17180131327 |
| 18 | 68720001023 |
| 19 | 274878955519 |
| 20 | 1099513724927 |
| 21 | 4398050705407 |
| 22 | 17592194433023 |
| 23 | 70368760954879 |
| 24 | 281475010265087 |
| 25 | 1125899973951487 |