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) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 84 |
| 4 | 1428 |
| 5 | 31416 |
| 6 | 848232 |
| 7 | 27143424 |
| 8 | 1004306688 |
| 9 | 42180880896 |
| 10 | 1982501402112 |
| 11 | 103090072909824 |
| 12 | 5876134155859968 |
| 13 | 364320317663318016 |
| 14 | 24409461283442307072 |
| 15 | 1757481212407846109184 |
| 16 | 135326053355404150407168 |
| 17 | 11096736375143140333387776 |
| 18 | 965416064637453209004736512 |