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 | 0 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 40 |
| 6 | 113 |
| 7 | 320 |
| 8 | 906 |
| 9 | 2565 |
| 10 | 7262 |
| 11 | 20560 |
| 12 | 58209 |
| 13 | 164800 |
| 14 | 466578 |
| 15 | 1320965 |
| 16 | 3739886 |
| 17 | 10588280 |
| 18 | 29977297 |
| 19 | 84871040 |
| 20 | 240284954 |
| 21 | 680289285 |
| 22 | 1926019518 |
| 23 | 5452902560 |
| 24 | 15438133441 |
| 25 | 43708091520 |
| 26 | 123745352482 |
| 27 | 350345021445 |