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) |
|---|---|
| 6 | 1 |
| 7 | 42 |
| 8 | 1204 |
| 9 | 29736 |
| 10 | 689850 |
| 11 | 15647940 |
| 12 | 354718980 |
| 13 | 8137289160 |
| 14 | 190349674515 |
| 15 | 4561677870750 |
| 16 | 112317990384600 |
| 17 | 2846259737521200 |
| 18 | 74306186469414900 |
| 19 | 1999421553976446600 |
| 20 | 55458660913310655000 |
| 21 | 1585528821898619598000 |