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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 15 |
| 7 | 32 |
| 8 | 94 |
| 9 | 295 |
| 10 | 1169 |
| 11 | 4870 |
| 12 | 22110 |
| 13 | 102490 |
| 14 | 489479 |
| 15 | 2370856 |
| 16 | 11655722 |
| 17 | 57918613 |
| 18 | 290697549 |
| 19 | 1471349079 |
| 20 | 7504192109 |
| 21 | 38532719288 |
| 22 | 199076246027 |
| 23 | 1034236802988 |
| 24 | 5400337234593 |
| 25 | 28329240686563 |
| 26 | 149244907924935 |
| 27 | 789351357094770 |
| 28 | 4190055030317638 |