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 | 13 |
| 2 | 169 |
| 3 | 677 |
| 4 | 4219 |
| 5 | 21517 |
| 6 | 119965 |
| 7 | 644401 |
| 8 | 3523073 |
| 9 | 19109897 |
| 10 | 103977527 |
| 11 | 564853957 |
| 12 | 3070715725 |
| 13 | 16689263845 |
| 14 | 90719255481 |
| 15 | 493099242743 |
| 16 | 2680257849413 |
| 17 | 14568413911287 |
| 18 | 79186365292369 |
| 19 | 430415795271435 |
| 20 | 2339519840411823 |