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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 1 |
| 10 | 253 |
| 11 | 925 |
| 12 | 2509 |
| 13 | 6007 |
| 14 | 13443 |
| 15 | 785643 |
| 16 | 6114551 |
| 17 | 31980469 |
| 18 | 138704361 |
| 19 | 539262713 |
| 20 | 13685913105 |
| 21 | 170996304653 |
| 22 | 1442111683785 |
| 23 | 9802624250281 |
| 24 | 58233700998845 |
| 25 | 939069565583991 |
| 26 | 15109164547164171 |
| 27 | 181402703206632211 |
| 28 | 1758154702415920051 |