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) |
|---|---|
| 3 | 6 |
| 4 | 12 |
| 5 | 50 |
| 6 | 180 |
| 7 | 497 |
| 8 | 1484 |
| 9 | 5154 |
| 10 | 13680 |
| 11 | 41327 |
| 12 | 134508 |
| 13 | 368095 |
| 14 | 1095367 |
| 15 | 3521156 |
| 16 | 9733564 |
| 17 | 29025290 |
| 18 | 92208816 |
| 19 | 257946527 |
| 20 | 769203752 |
| 21 | 2428043309 |
| 22 | 6848294497 |
| 23 | 20442949562 |
| 24 | 64191187508 |
| 25 | 182286409175 |
| 26 | 544512163065 |
| 27 | 1702858693902 |
| 28 | 4861764643419 |
| 29 | 14531465607434 |