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 | 75 |
| 2 | 2775 |
| 3 | 67525 |
| 4 | 1215450 |
| 5 | 17259390 |
| 6 | 201359550 |
| 7 | 1984829850 |
| 8 | 16871053725 |
| 9 | 125595622175 |
| 10 | 828931106355 |
| 11 | 4898229264825 |
| 12 | 26123889412400 |
| 13 | 126600387152400 |
| 14 | 560658857389200 |
| 15 | 2280012686716080 |
| 16 | 8550047575185300 |
| 17 | 29673694525643100 |
| 18 | 95615237915961100 |