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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 26 |
| 5 | 102 |
| 6 | 420 |
| 7 | 1787 |
| 8 | 7794 |
| 9 | 34666 |
| 10 | 156636 |
| 11 | 716982 |
| 12 | 3317700 |
| 13 | 15494156 |
| 14 | 72935624 |
| 15 | 345701843 |
| 16 | 1648489762 |
| 17 | 7902956738 |
| 18 | 38067806892 |
| 19 | 184152092450 |
| 20 | 894259126540 |
| 21 | 4357738501844 |
| 22 | 21302682030328 |
| 23 | 104439435098718 |
| 24 | 513390992000340 |
| 25 | 2529846489669412 |
| 26 | 12494572784556440 |