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 | 2 |
| 3 | 5 |
| 4 | 12 |
| 5 | 34 |
| 6 | 116 |
| 7 | 449 |
| 8 | 1897 |
| 9 | 8469 |
| 10 | 38959 |
| 11 | 182511 |
| 12 | 865612 |
| 13 | 4140438 |
| 14 | 19937335 |
| 15 | 96519210 |
| 16 | 469387311 |
| 17 | 2291623939 |
| 18 | 11226534301 |
| 19 | 55165698564 |
| 20 | 271816734576 |
| 21 | 1342610043518 |