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 | 4 |
| 2 | 15 |
| 3 | 56 |
| 4 | 207 |
| 5 | 764 |
| 6 | 2805 |
| 7 | 10288 |
| 8 | 37609 |
| 9 | 137380 |
| 10 | 500655 |
| 11 | 1823440 |
| 12 | 6629423 |
| 13 | 24090332 |
| 14 | 87418221 |
| 15 | 317085352 |
| 16 | 1148825185 |
| 17 | 4160744164 |
| 18 | 15054719697 |
| 19 | 54454345624 |
| 20 | 196805925995 |
| 21 | 711077858188 |
| 22 | 2567375653681 |
| 23 | 9267176552040 |
| 24 | 33430012251123 |
| 25 | 120565130387572 |
| 26 | 434578910451203 |