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) |
|---|---|
| 4 | 3 |
| 5 | 11 |
| 6 | 37 |
| 7 | 124 |
| 8 | 420 |
| 9 | 1441 |
| 10 | 5005 |
| 11 | 17576 |
| 12 | 62322 |
| 13 | 222870 |
| 14 | 802978 |
| 15 | 2912168 |
| 16 | 10623470 |
| 17 | 38956365 |
| 18 | 143521725 |
| 19 | 530985360 |
| 20 | 1971965490 |
| 21 | 7348812570 |
| 22 | 27472909590 |
| 23 | 103002205800 |
| 24 | 387205269360 |
| 25 | 1459146890058 |
| 26 | 5511120747282 |
| 27 | 20858962792624 |
| 28 | 79103096214100 |