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 | 2 |
| 1 | 4 |
| 2 | 18 |
| 3 | 76 |
| 4 | 322 |
| 5 | 1364 |
| 6 | 5778 |
| 7 | 24476 |
| 8 | 103682 |
| 9 | 439204 |
| 10 | 1860498 |
| 11 | 7881196 |
| 12 | 33385282 |
| 13 | 141422324 |
| 14 | 599074578 |
| 15 | 2537720636 |
| 16 | 10749957122 |
| 17 | 45537549124 |
| 18 | 192900153618 |
| 19 | 817138163596 |
| 20 | 3461452808002 |
| 21 | 14662949395604 |
| 22 | 62113250390418 |