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 | 16 |
| 2 | 50 |
| 3 | 176 |
| 4 | 738 |
| 5 | 3408 |
| 6 | 16402 |
| 7 | 80368 |
| 8 | 397250 |
| 9 | 1972880 |
| 10 | 9824754 |
| 11 | 49005360 |
| 12 | 244672162 |
| 13 | 1222297552 |
| 14 | 6108298706 |
| 15 | 30531927152 |
| 16 | 152630937474 |
| 17 | 763068593424 |
| 18 | 3815084686258 |
| 19 | 19074648589744 |
| 20 | 95370918425186 |
| 21 | 476847618556496 |