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 | 2 |
| 2 | 1 |
| 3 | 0 |
| 4 | 17 |
| 5 | 118 |
| 6 | 513 |
| 7 | 1844 |
| 8 | 6049 |
| 9 | 18954 |
| 10 | 58049 |
| 11 | 175816 |
| 12 | 529713 |
| 13 | 1592126 |
| 14 | 4780225 |
| 15 | 14345532 |
| 16 | 43042625 |
| 17 | 129135250 |
| 18 | 387414657 |
| 19 | 1162254608 |
| 20 | 3486776401 |
| 21 | 10460343942 |
| 22 | 31381048961 |
| 23 | 94143166660 |
| 24 | 282429522657 |
| 25 | 847288593818 |