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 | 2 |
| 1 | 5 |
| 2 | 13 |
| 3 | 41 |
| 4 | 145 |
| 5 | 545 |
| 6 | 2113 |
| 7 | 8321 |
| 8 | 33025 |
| 9 | 131585 |
| 10 | 525313 |
| 11 | 2099201 |
| 12 | 8392705 |
| 13 | 33562625 |
| 14 | 134234113 |
| 15 | 536903681 |
| 16 | 2147549185 |
| 17 | 8590065665 |
| 18 | 34360000513 |
| 19 | 137439477761 |
| 20 | 549756862465 |
| 21 | 2199025352705 |
| 22 | 8796097216513 |
| 23 | 35184380477441 |
| 24 | 140737505132545 |
| 25 | 562949986975745 |
| 26 | 2251799880794113 |