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 | 4 |
| 2 | 17 |
| 3 | 69 |
| 4 | 281 |
| 5 | 1147 |
| 6 | 4784 |
| 7 | 20345 |
| 8 | 88726 |
| 9 | 396971 |
| 10 | 1823920 |
| 11 | 8605364 |
| 12 | 41684417 |
| 13 | 207201343 |
| 14 | 1056244832 |
| 15 | 5518054182 |
| 16 | 29521703655 |
| 17 | 161625956908 |
| 18 | 904857279576 |
| 19 | 5176569819167 |
| 20 | 30241443710950 |
| 21 | 180293374961036 |
| 22 | 1096240011165724 |
| 23 | 6793998104717138 |
| 24 | 42894087222036022 |
| 25 | 275735424352928682 |