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 | 2 |
| 3 | 7 |
| 4 | 28 |
| 5 | 122 |
| 6 | 556 |
| 7 | 2618 |
| 8 | 12634 |
| 9 | 62128 |
| 10 | 310212 |
| 11 | 1568495 |
| 12 | 8014742 |
| 13 | 41323641 |
| 14 | 214719610 |
| 15 | 1123244757 |
| 16 | 5910863420 |
| 17 | 31268459118 |
| 18 | 166185855552 |
| 19 | 886961294034 |
| 20 | 4751819567488 |
| 21 | 25545030878475 |
| 22 | 137756210983218 |
| 23 | 745003421378887 |
| 24 | 4039670554117446 |
| 25 | 21957581725458521 |