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 | 25 |
| 3 | 113 |
| 4 | 481 |
| 5 | 1985 |
| 6 | 8065 |
| 7 | 32513 |
| 8 | 130561 |
| 9 | 523265 |
| 10 | 2095105 |
| 11 | 8384513 |
| 12 | 33546241 |
| 13 | 134201345 |
| 14 | 536838145 |
| 15 | 2147418113 |
| 16 | 8589803521 |
| 17 | 34359476225 |
| 18 | 137438429185 |
| 19 | 549754765313 |
| 20 | 2199021158401 |
| 21 | 8796088827905 |
| 22 | 35184363700225 |