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 | 12 |
| 3 | 46 |
| 4 | 174 |
| 5 | 654 |
| 6 | 2451 |
| 7 | 9177 |
| 8 | 34368 |
| 9 | 128826 |
| 10 | 483531 |
| 11 | 1817673 |
| 12 | 6844294 |
| 13 | 25815660 |
| 14 | 97539435 |
| 15 | 369154485 |
| 16 | 1399419360 |
| 17 | 5313440610 |
| 18 | 20205330660 |
| 19 | 76946898744 |
| 20 | 293443125804 |
| 21 | 1120565939780 |
| 22 | 4284550682478 |
| 23 | 16402204879386 |
| 24 | 62864294076480 |
| 25 | 241205747620740 |