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) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 40 |
| 6 | 187 |
| 7 | 854 |
| 8 | 4074 |
| 9 | 19602 |
| 10 | 96035 |
| 11 | 475492 |
| 12 | 2380042 |
| 13 | 12015368 |
| 14 | 61130186 |
| 15 | 313081232 |
| 16 | 1612967974 |
| 17 | 8353387992 |
| 18 | 43464071199 |
| 19 | 227101948596 |
| 20 | 1191127734498 |
| 21 | 6268882232536 |
| 22 | 33096647906860 |
| 23 | 175236408484988 |
| 24 | 930271133498794 |
| 25 | 4950509216635406 |
| 26 | 26403755607304762 |
| 27 | 141119182968584618 |