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 | 1 |
| 1 | 13 |
| 2 | 121 |
| 3 | 997 |
| 4 | 7729 |
| 5 | 57853 |
| 6 | 423721 |
| 7 | 3059797 |
| 8 | 21887329 |
| 9 | 155555053 |
| 10 | 1100604121 |
| 11 | 7762822597 |
| 12 | 54632726929 |
| 13 | 383893932253 |
| 14 | 2694581744521 |
| 15 | 18898693305397 |
| 16 | 132473958606529 |
| 17 | 928233237589453 |
| 18 | 6502210299844921 |
| 19 | 45538360282508197 |
| 20 | 318882962895526129 |
| 21 | 2232752944858526653 |