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 | 4 |
| 2 | 9 |
| 3 | 21 |
| 4 | 49 |
| 5 | 65 |
| 6 | 86 |
| 7 | 265 |
| 8 | 1081 |
| 9 | 1897 |
| 10 | 2513 |
| 11 | 7739 |
| 12 | 97229 |
| 13 | 128801 |
| 14 | 299426 |
| 15 | 922111 |
| 16 | 1221537 |
| 17 | 2839729 |
| 18 | 62608681 |
| 19 | 338356945 |
| 20 | 53406819691 |
| 21 | 2066337330754 |
| 22 | 6363483400447 |
| 23 | 8429820731201 |
| 24 | 432062194544201 |
| 25 | 7190854504969591 |
| 26 | 12619069972000553 |
| 27 | 16716708595637087 |