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 | 5 |
| 3 | 21 |
| 4 | 73 |
| 5 | 233 |
| 6 | 717 |
| 7 | 2173 |
| 8 | 6545 |
| 9 | 19665 |
| 10 | 59029 |
| 11 | 177125 |
| 12 | 531417 |
| 13 | 1594297 |
| 14 | 4782941 |
| 15 | 14348877 |
| 16 | 43046689 |
| 17 | 129140129 |
| 18 | 387420453 |
| 19 | 1162261429 |
| 20 | 3486784361 |
| 21 | 10460353161 |
| 22 | 31381059565 |
| 23 | 94143178781 |
| 24 | 282429536433 |
| 25 | 847288609393 |
| 26 | 2541865828277 |
| 27 | 7625597484933 |
| 28 | 22876792454905 |
| 29 | 68630377364825 |