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 | 5 |
| 3 | 14 |
| 4 | 42 |
| 5 | 132 |
| 6 | 428 |
| 7 | 1416 |
| 8 | 4745 |
| 9 | 16034 |
| 10 | 54505 |
| 11 | 186166 |
| 12 | 638538 |
| 13 | 2198692 |
| 14 | 7598624 |
| 15 | 26350944 |
| 16 | 91670946 |
| 17 | 319825796 |
| 18 | 1118686730 |
| 19 | 3921801820 |
| 20 | 13775938132 |
| 21 | 48473233032 |
| 22 | 170815501576 |
| 23 | 602710956464 |
| 24 | 2128981351316 |
| 25 | 7527515059432 |
| 26 | 26637591204996 |
| 27 | 94331697697688 |