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 | 1 |
| 2 | 9 |
| 3 | 69 |
| 4 | 317 |
| 5 | 1741 |
| 6 | 9385 |
| 7 | 50035 |
| 8 | 268453 |
| 9 | 1438203 |
| 10 | 7705011 |
| 11 | 41284941 |
| 12 | 221198177 |
| 13 | 1185157449 |
| 14 | 6349965025 |
| 15 | 34022467117 |
| 16 | 182289038899 |
| 17 | 976686732167 |
| 18 | 5232991207579 |
| 19 | 28037851489661 |
| 20 | 150224045883455 |
| 21 | 804885636881145 |