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 | 3 |
| 3 | 9 |
| 4 | 28 |
| 5 | 90 |
| 6 | 282 |
| 7 | 875 |
| 8 | 2700 |
| 9 | 8271 |
| 10 | 25265 |
| 11 | 77088 |
| 12 | 235014 |
| 13 | 716261 |
| 14 | 2182257 |
| 15 | 6646200 |
| 16 | 20234080 |
| 17 | 61581327 |
| 18 | 187366482 |
| 19 | 569947883 |
| 20 | 1733389620 |
| 21 | 5270937735 |
| 22 | 16025807017 |
| 23 | 48719131461 |
| 24 | 148092422604 |
| 25 | 450116618125 |
| 26 | 1367983011213 |
| 27 | 4157227183617 |