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 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 33 |
| 6 | 81 |
| 7 | 193 |
| 8 | 449 |
| 9 | 1089 |
| 10 | 2673 |
| 11 | 6561 |
| 12 | 15633 |
| 13 | 37249 |
| 14 | 88209 |
| 15 | 216513 |
| 16 | 531441 |
| 17 | 1266273 |
| 18 | 3017169 |
| 19 | 7189057 |
| 20 | 17537553 |
| 21 | 43046721 |
| 22 | 102568113 |
| 23 | 244390689 |
| 24 | 582313617 |
| 25 | 1420541793 |
| 26 | 3486784401 |
| 27 | 8308017153 |
| 28 | 19795645809 |
| 29 | 47167402977 |
| 30 | 115063885233 |
| 31 | 282429536481 |