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 | 0 |
| 1 | 1 |
| 2 | 19 |
| 3 | 301 |
| 4 | 4659 |
| 5 | 73651 |
| 6 | 1208849 |
| 7 | 20736801 |
| 8 | 372683159 |
| 9 | 7020426511 |
| 10 | 138543438429 |
| 11 | 2861318625661 |
| 12 | 61767341913539 |
| 13 | 1391789835244251 |
| 14 | 32689488282841529 |
| 15 | 799220290375798681 |
| 16 | 20312800343333343279 |
| 17 | 535995638431063608871 |
| 18 | 14665906835087251866389 |