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 | 4 |
| 3 | 12 |
| 4 | 76 |
| 5 | 630 |
| 6 | 7968 |
| 7 | 117656 |
| 8 | 2105416 |
| 9 | 43048917 |
| 10 | 1000781420 |
| 11 | 25937424612 |
| 12 | 743130116112 |
| 13 | 23298085122494 |
| 14 | 793742455829456 |
| 15 | 29192926758107760 |
| 16 | 1152930300766980112 |
| 17 | 48661191875666868498 |
| 18 | 2185915267189632382650 |
| 19 | 104127350297911241532860 |