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 | 8 |
| 2 | 30 |
| 3 | 134 |
| 4 | 642 |
| 5 | 3158 |
| 6 | 15690 |
| 7 | 78254 |
| 8 | 390882 |
| 9 | 1953638 |
| 10 | 9766650 |
| 11 | 48830174 |
| 12 | 244144722 |
| 13 | 1220711318 |
| 14 | 6103532010 |
| 15 | 30517610894 |
| 16 | 152587956162 |
| 17 | 762939584198 |
| 18 | 3814697527770 |
| 19 | 19073486852414 |
| 20 | 95367432689202 |
| 21 | 476837160300278 |