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 | 2 |
| 7 | 6 |
| 8 | 14 |
| 9 | 24 |
| 10 | 46 |
| 11 | 88 |
| 12 | 162 |
| 13 | 300 |
| 14 | 562 |
| 15 | 1056 |
| 16 | 1982 |
| 17 | 3742 |
| 18 | 7082 |
| 19 | 13438 |
| 20 | 25574 |
| 21 | 48768 |
| 22 | 93198 |
| 23 | 178480 |
| 24 | 342392 |
| 25 | 657918 |
| 26 | 1266202 |
| 27 | 2440318 |
| 28 | 4709374 |
| 29 | 9099504 |
| 30 | 17602322 |
| 31 | 34087010 |
| 32 | 66076414 |
| 33 | 128207976 |
| 34 | 248983550 |
| 35 | 483939976 |
| 36 | 941362694 |
| 37 | 1832519262 |
| 38 | 3569842946 |
| 39 | 6958934352 |