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 | 7 |
| 1 | 27 |
| 2 | 119 |
| 3 | 427 |
| 4 | 1799 |
| 5 | 6939 |
| 6 | 30583 |
| 7 | 109227 |
| 8 | 458759 |
| 9 | 1769499 |
| 10 | 7798903 |
| 11 | 27984299 |
| 12 | 117901063 |
| 13 | 454761243 |
| 14 | 2004318071 |
| 15 | 7158278827 |
| 16 | 30064771079 |
| 17 | 115964117019 |
| 18 | 511101108343 |
| 19 | 1833951035819 |
| 20 | 7726646167303 |