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 | 1 |
| 1 | 7 |
| 2 | 9 |
| 3 | 23 |
| 4 | 41 |
| 5 | 87 |
| 6 | 169 |
| 7 | 343 |
| 8 | 681 |
| 9 | 1367 |
| 10 | 2729 |
| 11 | 5463 |
| 12 | 10921 |
| 13 | 21847 |
| 14 | 43689 |
| 15 | 87383 |
| 16 | 174761 |
| 17 | 349527 |
| 18 | 699049 |
| 19 | 1398103 |
| 20 | 2796201 |
| 21 | 5592407 |
| 22 | 11184809 |
| 23 | 22369623 |
| 24 | 44739241 |
| 25 | 89478487 |
| 26 | 178956969 |
| 27 | 357913943 |
| 28 | 715827881 |
| 29 | 1431655767 |
| 30 | 2863311529 |