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 | 7 |
| 3 | 9 |
| 4 | 21 |
| 5 | 63 |
| 6 | 107 |
| 7 | 189 |
| 8 | 273 |
| 9 | 819 |
| 10 | 1911 |
| 11 | 2457 |
| 12 | 5189 |
| 13 | 15567 |
| 14 | 28123 |
| 15 | 46701 |
| 16 | 65793 |
| 17 | 197379 |
| 18 | 460551 |
| 19 | 592137 |
| 20 | 1381653 |
| 21 | 4144959 |
| 22 | 7039851 |
| 23 | 12434877 |
| 24 | 17829905 |
| 25 | 53489715 |
| 26 | 124809335 |
| 27 | 160469145 |
| 28 | 340873541 |
| 29 | 1022620623 |
| 30 | 1840690907 |