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 | 3 |
| 1 | 142 |
| 2 | 71 |
| 3 | 3338 |
| 4 | 1669 |
| 5 | 78444 |
| 6 | 39222 |
| 7 | 19611 |
| 8 | 921718 |
| 9 | 460859 |
| 10 | 21660374 |
| 11 | 10830187 |
| 12 | 509018790 |
| 13 | 254509395 |
| 14 | 11961941566 |
| 15 | 5980970783 |
| 16 | 281105626802 |
| 17 | 140552813401 |
| 18 | 6605982229848 |
| 19 | 3302991114924 |
| 20 | 1651495557462 |