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 | 7 |
| 4 | 29 |
| 5 | 131 |
| 6 | 625 |
| 7 | 3099 |
| 8 | 15818 |
| 9 | 82595 |
| 10 | 439259 |
| 11 | 2371632 |
| 12 | 12967707 |
| 13 | 71669167 |
| 14 | 399751019 |
| 15 | 2247488837 |
| 16 | 12723799989 |
| 17 | 72474333715 |
| 18 | 415046380767 |
| 19 | 2388355096446 |
| 20 | 13803034008095 |
| 21 | 80082677184820 |
| 22 | 466263828731640 |
| 23 | 2723428895205210 |
| 24 | 15954063529603565 |
| 25 | 93711351580424391 |