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) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 6 |
| 8 | 17 |
| 9 | 73 |
| 10 | 389 |
| 11 | 2274 |
| 12 | 14502 |
| 13 | 97033 |
| 14 | 672781 |
| 15 | 4792530 |
| 16 | 34911786 |
| 17 | 259106122 |
| 18 | 1954315346 |
| 19 | 14949368524 |
| 20 | 115784496932 |
| 21 | 906736988527 |
| 22 | 7171613842488 |
| 23 | 57231089062625 |
| 24 | 460428456484557 |
| 25 | 3731572377382341 |
| 26 | 30447133566946517 |
| 27 | 249968326771680542 |
| 28 | 2063931874299323140 |