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 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 4 |
| 5 | 6 |
| 6 | 36 |
| 7 | 117 |
| 8 | 804 |
| 9 | 4266 |
| 10 | 33768 |
| 11 | 249144 |
| 12 | 2289348 |
| 13 | 21353472 |
| 14 | 227212824 |
| 15 | 2533824900 |
| 16 | 30914509212 |
| 17 | 398623158096 |
| 18 | 5508014798052 |
| 19 | 80377645583430 |
| 20 | 1242697826967816 |
| 21 | 20218588415853480 |
| 22 | 346035438765576720 |
| 23 | 6206862951272939550 |
| 24 | 116518581654518098332 |