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 | 5 |
| 2 | 21 |
| 3 | 90 |
| 4 | 387 |
| 5 | 1665 |
| 6 | 7164 |
| 7 | 30825 |
| 8 | 132633 |
| 9 | 570690 |
| 10 | 2455551 |
| 11 | 10565685 |
| 12 | 45461772 |
| 13 | 195611805 |
| 14 | 841673709 |
| 15 | 3621533130 |
| 16 | 15582644523 |
| 17 | 67048623225 |
| 18 | 288495182556 |
| 19 | 1241330043105 |
| 20 | 5341164667857 |
| 21 | 22981833209970 |
| 22 | 98885672046279 |