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 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 19 |
| 7 | 56 |
| 8 | 160 |
| 9 | 463 |
| 10 | 1337 |
| 11 | 3874 |
| 12 | 11241 |
| 13 | 32682 |
| 14 | 95172 |
| 15 | 277577 |
| 16 | 810706 |
| 17 | 2370839 |
| 18 | 6941473 |
| 19 | 20345618 |
| 20 | 59692831 |
| 21 | 175295996 |
| 22 | 515217034 |
| 23 | 1515478535 |
| 24 | 4460940067 |
| 25 | 13140081770 |
| 26 | 38729776774 |
| 27 | 114221851951 |
| 28 | 337050020750 |
| 29 | 995097461503 |
| 30 | 2939337252651 |
| 31 | 8686270661400 |