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 | 4 |
| 1 | 17 |
| 2 | 140 |
| 3 | 577 |
| 4 | 4756 |
| 5 | 19601 |
| 6 | 161564 |
| 7 | 665857 |
| 8 | 5488420 |
| 9 | 22619537 |
| 10 | 186444716 |
| 11 | 768398401 |
| 12 | 6333631924 |
| 13 | 26102926097 |
| 14 | 215157040700 |
| 15 | 886731088897 |
| 16 | 7309005751876 |
| 17 | 30122754096401 |
| 18 | 248291038523084 |