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 | 51 |
| 3 | 385 |
| 4 | 2995 |
| 5 | 23877 |
| 6 | 194109 |
| 7 | 1602447 |
| 8 | 13389075 |
| 9 | 112935445 |
| 10 | 959783881 |
| 11 | 8206116387 |
| 12 | 70507643101 |
| 13 | 608271899515 |
| 14 | 5265458413875 |
| 15 | 45711784088145 |
| 16 | 397829544860115 |
| 17 | 3469772959954245 |
| 18 | 30319709631711225 |
| 19 | 265383615634224675 |
| 20 | 2326318766651511945 |
| 21 | 20419439617056272415 |