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) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 21 |
| 4 | 51 |
| 5 | 111 |
| 6 | 249 |
| 7 | 525 |
| 8 | 1119 |
| 9 | 2319 |
| 10 | 4809 |
| 11 | 9825 |
| 12 | 20079 |
| 13 | 40671 |
| 14 | 82341 |
| 15 | 165945 |
| 16 | 334191 |
| 17 | 671307 |
| 18 | 1347861 |
| 19 | 2702385 |
| 20 | 5416395 |
| 21 | 10847787 |
| 22 | 21720981 |
| 23 | 43474869 |
| 24 | 87004875 |
| 25 | 174081051 |
| 26 | 348279777 |
| 27 | 696712749 |
| 28 | 1393674603 |
| 29 | 2787673767 |
| 30 | 5575871457 |
| 31 | 11152425093 |
| 32 | 22305942039 |