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 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 15 |
| 6 | 44 |
| 7 | 128 |
| 8 | 415 |
| 9 | 1367 |
| 10 | 4654 |
| 11 | 16080 |
| 12 | 56450 |
| 13 | 200170 |
| 14 | 716728 |
| 15 | 2585850 |
| 16 | 9393119 |
| 17 | 34319667 |
| 18 | 126047906 |
| 19 | 465076160 |
| 20 | 1723097066 |
| 21 | 6407856892 |
| 22 | 23910271224 |
| 23 | 89493903438 |
| 24 | 335912741682 |
| 25 | 1264106399934 |
| 26 | 4768448177636 |
| 27 | 18027218147818 |