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 | 2 |
| 3 | 11 |
| 4 | 54 |
| 5 | 260 |
| 6 | 1247 |
| 7 | 5982 |
| 8 | 28741 |
| 9 | 138364 |
| 10 | 667488 |
| 11 | 3226503 |
| 12 | 15625476 |
| 13 | 75802578 |
| 14 | 368316888 |
| 15 | 1792203759 |
| 16 | 8732274312 |
| 17 | 42598366616 |
| 18 | 208036945958 |
| 19 | 1017023261529 |
| 20 | 4976560342522 |
| 21 | 24372741339016 |
| 22 | 119461561111023 |
| 23 | 585970198529224 |