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) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 7 |
| 9 | 12 |
| 10 | 23 |
| 11 | 44 |
| 12 | 81 |
| 13 | 150 |
| 14 | 281 |
| 15 | 528 |
| 16 | 991 |
| 17 | 1871 |
| 18 | 3541 |
| 19 | 6719 |
| 20 | 12787 |
| 21 | 24384 |
| 22 | 46599 |
| 23 | 89240 |
| 24 | 171196 |
| 25 | 328959 |
| 26 | 633101 |
| 27 | 1220159 |
| 28 | 2354687 |
| 29 | 4549752 |
| 30 | 8801161 |
| 31 | 17043505 |
| 32 | 33038207 |
| 33 | 64103988 |
| 34 | 124491775 |
| 35 | 241969988 |
| 36 | 470681347 |
| 37 | 916259631 |
| 38 | 1784921473 |
| 39 | 3479467176 |
| 40 | 6787108712 |
| 41 | 13247128044 |
| 42 | 25870861823 |