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 | 0 |
| 1 | 2 |
| 2 | 4 |
| 3 | 11 |
| 4 | 25 |
| 5 | 65 |
| 6 | 168 |
| 7 | 446 |
| 8 | 1229 |
| 9 | 3401 |
| 10 | 9592 |
| 11 | 27293 |
| 12 | 78498 |
| 13 | 227647 |
| 14 | 664579 |
| 15 | 1951957 |
| 16 | 5761455 |
| 17 | 17082666 |
| 18 | 50847534 |
| 19 | 151876932 |
| 20 | 455052511 |
| 21 | 1367199811 |
| 22 | 4118054813 |
| 23 | 12431880460 |
| 24 | 37607912018 |
| 25 | 113983535775 |
| 26 | 346065536839 |
| 27 | 1052370166553 |
| 28 | 3204941750802 |
| 29 | 9773865306521 |