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 | 4 |
| 3 | 13 |
| 4 | 40 |
| 5 | 120 |
| 6 | 356 |
| 7 | 1050 |
| 8 | 3088 |
| 9 | 9069 |
| 10 | 26620 |
| 11 | 78133 |
| 12 | 229384 |
| 13 | 673699 |
| 14 | 1979628 |
| 15 | 5820195 |
| 16 | 17121312 |
| 17 | 50394579 |
| 18 | 148413996 |
| 19 | 437324919 |
| 20 | 1289330520 |
| 21 | 3803175474 |
| 22 | 11223840012 |
| 23 | 33139076292 |
| 24 | 97889042384 |
| 25 | 289276841475 |
| 26 | 855205791076 |
| 27 | 2529279459099 |