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 | 4 |
| 2 | 10 |
| 3 | 26 |
| 4 | 69 |
| 5 | 181 |
| 6 | 455 |
| 7 | 1120 |
| 8 | 2794 |
| 9 | 6955 |
| 10 | 17254 |
| 11 | 42770 |
| 12 | 105825 |
| 13 | 262026 |
| 14 | 648672 |
| 15 | 1605786 |
| 16 | 3974375 |
| 17 | 9835789 |
| 18 | 24343416 |
| 19 | 60250311 |
| 20 | 149117782 |
| 21 | 369056036 |
| 22 | 913396093 |
| 23 | 2260628044 |
| 24 | 5594995167 |
| 25 | 13847440350 |
| 26 | 34272006253 |
| 27 | 84822308047 |
| 28 | 209933077581 |