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 | 19 |
| 3 | 103 |
| 4 | 616 |
| 5 | 3949 |
| 6 | 26545 |
| 7 | 184120 |
| 8 | 1303135 |
| 9 | 9341191 |
| 10 | 67490044 |
| 11 | 489978217 |
| 12 | 3567727441 |
| 13 | 26024391436 |
| 14 | 190036459099 |
| 15 | 1388593185079 |
| 16 | 10150390743088 |
| 17 | 74215146065461 |
| 18 | 542704850311009 |
| 19 | 3968914608295360 |
| 20 | 29026988765886535 |
| 21 | 212297824609934455 |
| 22 | 1552734183515322436 |