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 | 4 |
| 4 | 8 |
| 5 | 20 |
| 6 | 48 |
| 7 | 132 |
| 8 | 344 |
| 9 | 996 |
| 10 | 2720 |
| 11 | 8132 |
| 12 | 22888 |
| 13 | 69940 |
| 14 | 201040 |
| 15 | 624132 |
| 16 | 1822136 |
| 17 | 5725124 |
| 18 | 16915008 |
| 19 | 53648772 |
| 20 | 160012232 |
| 21 | 511360340 |
| 22 | 1536928624 |
| 23 | 4942300804 |
| 24 | 14949122328 |
| 25 | 48322714020 |
| 26 | 146946942688 |
| 27 | 477105960772 |
| 28 | 1457491035944 |
| 29 | 4750171491956 |
| 30 | 14568377075344 |