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 | 126 |
| 4 | 1484 |
| 5 | 18452 |
| 6 | 229698 |
| 7 | 2861964 |
| 8 | 35663964 |
| 9 | 444486280 |
| 10 | 5539931796 |
| 11 | 69048910000 |
| 12 | 860620499760 |
| 13 | 10726732430288 |
| 14 | 133697577587000 |
| 15 | 1666401898058352 |
| 16 | 20769976722986288 |
| 17 | 258876295158900832 |
| 18 | 3226625529605854320 |
| 19 | 40216553455854426560 |
| 20 | 501257787787122948736 |