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 | 9 |
| 3 | 33 |
| 4 | 145 |
| 5 | 609 |
| 6 | 2585 |
| 7 | 10945 |
| 8 | 46369 |
| 9 | 196417 |
| 10 | 832041 |
| 11 | 3524577 |
| 12 | 14930353 |
| 13 | 63245985 |
| 14 | 267914297 |
| 15 | 1134903169 |
| 16 | 4807526977 |
| 17 | 20365011073 |
| 18 | 86267571273 |
| 19 | 365435296161 |
| 20 | 1548008755921 |
| 21 | 6557470319841 |
| 22 | 27777890035289 |
| 23 | 117669030460993 |
| 24 | 498454011879265 |
| 25 | 2111485077978049 |