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 | 39 |
| 2 | 315 |
| 3 | 1687 |
| 4 | 7470 |
| 5 | 29634 |
| 6 | 109421 |
| 7 | 384105 |
| 8 | 1298613 |
| 9 | 4264835 |
| 10 | 13686456 |
| 11 | 43102644 |
| 12 | 133636825 |
| 13 | 408900987 |
| 14 | 1237114335 |
| 15 | 3706490479 |
| 16 | 11010661266 |
| 17 | 32463981270 |
| 18 | 95081107013 |
| 19 | 276820695645 |
| 20 | 801633669561 |