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 | 7 |
| 2 | 55 |
| 3 | 463 |
| 4 | 4039 |
| 5 | 35839 |
| 6 | 320503 |
| 7 | 2876335 |
| 8 | 25854247 |
| 9 | 232557151 |
| 10 | 2092490071 |
| 11 | 18830313487 |
| 12 | 169464432775 |
| 13 | 1525146340543 |
| 14 | 13726182847159 |
| 15 | 123535108753519 |
| 16 | 1111813831298023 |
| 17 | 10006315891747615 |
| 18 | 90056808665990167 |
| 19 | 810511140554958031 |
| 20 | 7294599715238808391 |