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 | 2 |
| 2 | 6 |
| 3 | 26 |
| 4 | 99 |
| 5 | 456 |
| 6 | 1898 |
| 7 | 9014 |
| 8 | 39336 |
| 9 | 190852 |
| 10 | 859314 |
| 11 | 4240598 |
| 12 | 19544133 |
| 13 | 97854958 |
| 14 | 459521694 |
| 15 | 2330612590 |
| 16 | 11118124352 |
| 17 | 57054108568 |
| 18 | 275911990190 |
| 19 | 1431214323258 |
| 20 | 7005088758798 |
| 21 | 36699584733594 |
| 22 | 181565142550974 |
| 23 | 959959866168434 |
| 24 | 4795243608222520 |
| 25 | 25566993157191804 |