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 | 2 |
| 2 | 6 |
| 3 | 16 |
| 4 | 45 |
| 5 | 121 |
| 6 | 338 |
| 7 | 929 |
| 8 | 2598 |
| 9 | 7261 |
| 10 | 20453 |
| 11 | 57738 |
| 12 | 163799 |
| 13 | 465778 |
| 14 | 1328697 |
| 15 | 3798473 |
| 16 | 10883314 |
| 17 | 31237935 |
| 18 | 89812975 |
| 19 | 258595806 |
| 20 | 745563123 |
| 21 | 2152093734 |
| 22 | 6218854285 |
| 23 | 17988163439 |
| 24 | 52078267380 |
| 25 | 150899028305 |
| 26 | 437571778542 |
| 27 | 1269754686051 |
| 28 | 3687025215421 |