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 | 4 |
| 3 | 15 |
| 4 | 52 |
| 5 | 165 |
| 6 | 486 |
| 7 | 1351 |
| 8 | 3592 |
| 9 | 9225 |
| 10 | 23050 |
| 11 | 56331 |
| 12 | 135180 |
| 13 | 319501 |
| 14 | 745486 |
| 15 | 1720335 |
| 16 | 3932176 |
| 17 | 8912913 |
| 18 | 20054034 |
| 19 | 44826643 |
| 20 | 99614740 |
| 21 | 220200981 |
| 22 | 484442134 |
| 23 | 1061158935 |
| 24 | 2315255832 |
| 25 | 5033164825 |