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 | 1 |
| 2 | 11 |
| 3 | 49 |
| 4 | 131 |
| 5 | 441 |
| 6 | 1499 |
| 7 | 5041 |
| 8 | 17155 |
| 9 | 58081 |
| 10 | 196331 |
| 11 | 664225 |
| 12 | 2246915 |
| 13 | 7601049 |
| 14 | 25714875 |
| 15 | 86992929 |
| 16 | 294294531 |
| 17 | 995591809 |
| 18 | 3368061131 |
| 19 | 11394068049 |
| 20 | 38545859971 |
| 21 | 130399709881 |
| 22 | 441139059867 |
| 23 | 1492362754129 |
| 24 | 5048627019523 |
| 25 | 17079382863841 |
| 26 | 57779138374059 |