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 | 3 |
| 1 | 9 |
| 2 | 31 |
| 3 | 106 |
| 4 | 365 |
| 5 | 1263 |
| 6 | 4388 |
| 7 | 15336 |
| 8 | 53871 |
| 9 | 190059 |
| 10 | 673222 |
| 11 | 2393291 |
| 12 | 8535397 |
| 13 | 30526712 |
| 14 | 109449848 |
| 15 | 393272258 |
| 16 | 1415768769 |
| 17 | 5105086517 |
| 18 | 18434398665 |
| 19 | 66647658995 |
| 20 | 241210652738 |
| 21 | 873773659486 |
| 22 | 3167642169823 |
| 23 | 11491042716338 |
| 24 | 41708741708554 |
| 25 | 151461799255253 |