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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 30 |
| 7 | 78 |
| 8 | 205 |
| 9 | 546 |
| 10 | 1476 |
| 11 | 4026 |
| 12 | 11070 |
| 13 | 30660 |
| 14 | 85410 |
| 15 | 239144 |
| 16 | 672605 |
| 17 | 1899120 |
| 18 | 5380830 |
| 19 | 15292914 |
| 20 | 43584804 |
| 21 | 124527988 |
| 22 | 356602950 |
| 23 | 1023295422 |
| 24 | 2941974270 |
| 25 | 8472886092 |
| 26 | 24441017580 |
| 27 | 70607383938 |