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 | 5 |
| 2 | 27 |
| 3 | 157 |
| 4 | 963 |
| 5 | 6141 |
| 6 | 40323 |
| 7 | 270845 |
| 8 | 1852419 |
| 9 | 12857341 |
| 10 | 90337283 |
| 11 | 641286141 |
| 12 | 4592533507 |
| 13 | 33139654653 |
| 14 | 240723001347 |
| 15 | 1758796578813 |
| 16 | 12916805074947 |
| 17 | 95300512382973 |
| 18 | 706044251602947 |
| 19 | 5250379998560253 |
| 20 | 39176121681444867 |