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) |
|---|---|
| 4 | 3 |
| 5 | 280 |
| 6 | 5265 |
| 7 | 47040 |
| 8 | 271250 |
| 9 | 1170288 |
| 10 | 4105710 |
| 11 | 12334080 |
| 12 | 32837805 |
| 13 | 79365000 |
| 14 | 177200023 |
| 15 | 370319040 |
| 16 | 731732820 |
| 17 | 1377981920 |
| 18 | 2488927500 |
| 19 | 4334174208 |
| 20 | 7307669895 |
| 21 | 11972250360 |
| 22 | 19116135885 |
| 23 | 29823640000 |
| 24 | 45562619718 |
| 25 | 68291480400 |
| 26 | 100588847450 |
| 27 | 145809331200 |