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 | 3 |
| 2 | 13 |
| 3 | 53 |
| 4 | 214 |
| 5 | 859 |
| 6 | 3439 |
| 7 | 13758 |
| 8 | 55035 |
| 9 | 220142 |
| 10 | 880571 |
| 11 | 3522287 |
| 12 | 14089151 |
| 13 | 56356606 |
| 14 | 225426424 |
| 15 | 901705698 |
| 16 | 3606822793 |
| 17 | 14427291173 |
| 18 | 57709164695 |
| 19 | 230836658783 |
| 20 | 923346635133 |
| 21 | 3693386540532 |
| 22 | 14773546162130 |
| 23 | 59094184648520 |