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 | 1 |
| 5 | 0 |
| 6 | 6 |
| 7 | 0 |
| 8 | 20 |
| 9 | 5 |
| 10 | 258 |
| 11 | 62 |
| 12 | 2510 |
| 13 | 914 |
| 14 | 24285 |
| 15 | 16403 |
| 16 | 263945 |
| 17 | 222240 |
| 18 | 3068971 |
| 19 | 3241157 |
| 20 | 35286928 |
| 21 | 46638022 |
| 22 | 426740187 |
| 23 | 650095127 |
| 24 | 5330192371 |
| 25 | 9185814630 |
| 26 | 67064945191 |
| 27 | 129902075662 |
| 28 | 864443143567 |
| 29 | 1833530501143 |
| 30 | 11336065334984 |
| 31 | 25990268638322 |