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 | 2 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 58 |
| 6 | 146 |
| 7 | 414 |
| 8 | 1206 |
| 9 | 3410 |
| 10 | 9634 |
| 11 | 27670 |
| 12 | 79926 |
| 13 | 230666 |
| 14 | 667058 |
| 15 | 1936174 |
| 16 | 5632662 |
| 17 | 16408866 |
| 18 | 47875650 |
| 19 | 139908774 |
| 20 | 409404630 |
| 21 | 1199368026 |
| 22 | 3517351890 |
| 23 | 10325547582 |
| 24 | 30339113718 |
| 25 | 89217594738 |
| 26 | 262561101282 |
| 27 | 773248631222 |
| 28 | 2278737199606 |