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) |
|---|---|
| 2 | 4 |
| 3 | 11 |
| 4 | 30 |
| 5 | 72 |
| 6 | 189 |
| 7 | 442 |
| 8 | 1059 |
| 9 | 2700 |
| 10 | 6472 |
| 11 | 15927 |
| 12 | 40121 |
| 13 | 100363 |
| 14 | 251761 |
| 15 | 637340 |
| 16 | 1617174 |
| 17 | 4124705 |
| 18 | 10553853 |
| 19 | 27067277 |
| 20 | 69709965 |
| 21 | 179993173 |
| 22 | 465769838 |
| 23 | 1208198861 |
| 24 | 3140421934 |
| 25 | 8179002208 |
| 26 | 21338685406 |
| 27 | 55762149115 |
| 28 | 145935689393 |