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 | 35 |
| 1 | 56 |
| 2 | 140 |
| 3 | 400 |
| 4 | 1225 |
| 5 | 3920 |
| 6 | 12936 |
| 7 | 43680 |
| 8 | 150150 |
| 9 | 523600 |
| 10 | 1847560 |
| 11 | 6584032 |
| 12 | 23661365 |
| 13 | 85652000 |
| 14 | 312018000 |
| 15 | 1142971200 |
| 16 | 4207562730 |
| 17 | 15557374800 |
| 18 | 57750861000 |
| 19 | 215145084000 |
| 20 | 804104751450 |
| 21 | 3014244096864 |
| 22 | 11329763650800 |
| 23 | 42691863032000 |
| 24 | 161238018415500 |
| 25 | 610258100044320 |