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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 18 |
| 5 | 52 |
| 6 | 154 |
| 7 | 450 |
| 8 | 1301 |
| 9 | 3753 |
| 10 | 10838 |
| 11 | 31327 |
| 12 | 90568 |
| 13 | 261813 |
| 14 | 756786 |
| 15 | 2187496 |
| 16 | 6323023 |
| 17 | 18277014 |
| 18 | 52830706 |
| 19 | 152709940 |
| 20 | 441415867 |
| 21 | 1275934888 |
| 22 | 3688154521 |
| 23 | 10660798289 |
| 24 | 30815580241 |
| 25 | 89074003241 |
| 26 | 257472939209 |
| 27 | 744238632362 |
| 28 | 2151259638423 |
| 29 | 6218325456983 |