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 | 3 |
| 2 | 19 |
| 3 | 174 |
| 4 | 1883 |
| 5 | 22323 |
| 6 | 280409 |
| 7 | 3666736 |
| 8 | 49386326 |
| 9 | 680431419 |
| 10 | 9544684113 |
| 11 | 135852904486 |
| 12 | 1957119390279 |
| 13 | 28482417043498 |
| 14 | 418119577938769 |
| 15 | 6184065626127498 |
| 16 | 92062362629472668 |
| 17 | 1378427894172778961 |
| 18 | 20744229318047760620 |
| 19 | 313606289763390553200 |
| 20 | 4760422971894347226659 |