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 | 2 |
| 3 | 5 |
| 4 | 20 |
| 5 | 109 |
| 6 | 784 |
| 7 | 6757 |
| 8 | 68240 |
| 9 | 787477 |
| 10 | 10224812 |
| 11 | 147512053 |
| 12 | 2340964372 |
| 13 | 40527565261 |
| 14 | 760095929840 |
| 15 | 15352212731933 |
| 16 | 332228417657960 |
| 17 | 7668868648772701 |
| 18 | 188085259070219000 |
| 19 | 4884294069438337429 |