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 | 1 |
| 2 | 15 |
| 3 | 111 |
| 4 | 561 |
| 5 | 2211 |
| 6 | 7293 |
| 7 | 21021 |
| 8 | 54483 |
| 9 | 129558 |
| 10 | 286858 |
| 11 | 598026 |
| 12 | 1184118 |
| 13 | 2242266 |
| 14 | 4083366 |
| 15 | 7184166 |
| 16 | 12257850 |
| 17 | 20348031 |
| 18 | 32951985 |
| 19 | 52179985 |
| 20 | 80958735 |
| 21 | 123288165 |
| 22 | 184562235 |
| 23 | 271965915 |
| 24 | 394962165 |
| 25 | 565884540 |
| 26 | 800652996 |
| 27 | 1119632580 |
| 28 | 1548656956 |