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 | 7 |
| 3 | 28 |
| 4 | 115 |
| 5 | 406 |
| 6 | 1492 |
| 7 | 5104 |
| 8 | 17611 |
| 9 | 59077 |
| 10 | 197242 |
| 11 | 649540 |
| 12 | 2127364 |
| 13 | 6908734 |
| 14 | 22325632 |
| 15 | 71744968 |
| 16 | 229600123 |
| 17 | 731794258 |
| 18 | 2324583475 |
| 19 | 7360989292 |
| 20 | 23245426690 |
| 21 | 73222477552 |
| 22 | 230128420012 |
| 23 | 721764371008 |
| 24 | 2259438436708 |
| 25 | 7060738412431 |
| 26 | 22029510754258 |
| 27 | 68630377423960 |