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 | 3 |
| 1 | 13 |
| 2 | 77 |
| 3 | 547 |
| 4 | 4193 |
| 5 | 33043 |
| 6 | 262937 |
| 7 | 2099467 |
| 8 | 16784033 |
| 9 | 134237923 |
| 10 | 1073801897 |
| 11 | 8590113787 |
| 12 | 68720012273 |
| 13 | 549757416403 |
| 14 | 4398051310457 |
| 15 | 35184386470507 |
| 16 | 281475019822913 |
| 17 | 2251799942956483 |
| 18 | 18014398897164617 |
| 19 | 144115189238641627 |