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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 20 |
| 7 | 49 |
| 8 | 132 |
| 9 | 330 |
| 10 | 786 |
| 11 | 1892 |
| 12 | 4472 |
| 13 | 10368 |
| 14 | 23940 |
| 15 | 54720 |
| 16 | 123836 |
| 17 | 278664 |
| 18 | 622896 |
| 19 | 1383672 |
| 20 | 3058720 |
| 21 | 6729184 |
| 22 | 14738688 |
| 23 | 32157312 |
| 24 | 69907200 |
| 25 | 151461952 |
| 26 | 327158208 |
| 27 | 704648448 |
| 28 | 1513680192 |
| 29 | 3243601280 |
| 30 | 6934595840 |
| 31 | 14793782400 |
| 32 | 31496441856 |
| 33 | 66929938944 |