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) |
|---|---|
| 1 | 4 |
| 2 | 1 |
| 3 | 4 |
| 4 | 5 |
| 5 | 11 |
| 6 | 34 |
| 7 | 88 |
| 8 | 271 |
| 9 | 798 |
| 10 | 2368 |
| 11 | 7071 |
| 12 | 21110 |
| 13 | 63163 |
| 14 | 188980 |
| 15 | 565622 |
| 16 | 1693239 |
| 17 | 5069374 |
| 18 | 15178832 |
| 19 | 45451143 |
| 20 | 136102762 |
| 21 | 407567006 |
| 22 | 1220499079 |
| 23 | 3654940301 |
| 24 | 10945255479 |
| 25 | 32777313021 |
| 26 | 98157159720 |
| 27 | 293948595170 |
| 28 | 880280943171 |