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) |
|---|---|
| 1 | 4 |
| 2 | 32 |
| 3 | 153 |
| 4 | 772 |
| 5 | 3818 |
| 6 | 19191 |
| 7 | 96004 |
| 8 | 481261 |
| 9 | 2411557 |
| 10 | 12086268 |
| 11 | 60572976 |
| 12 | 303579352 |
| 13 | 1521476119 |
| 14 | 7625336613 |
| 15 | 38216661796 |
| 16 | 191534345225 |
| 17 | 959932146275 |
| 18 | 4810989844333 |
| 19 | 24111728148027 |
| 20 | 120843206657400 |
| 21 | 605642220203867 |