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 | 5 |
| 2 | 31 |
| 3 | 141 |
| 4 | 659 |
| 5 | 3005 |
| 6 | 13739 |
| 7 | 62669 |
| 8 | 285931 |
| 9 | 1304285 |
| 10 | 5949691 |
| 11 | 27139821 |
| 12 | 123799979 |
| 13 | 564720125 |
| 14 | 2576001179 |
| 15 | 11750565389 |
| 16 | 53600825611 |
| 17 | 244502996765 |
| 18 | 1115313334651 |
| 19 | 5087560678701 |
| 20 | 23207176728299 |
| 21 | 105860762282045 |
| 22 | 482889457961819 |
| 23 | 2202725765240909 |