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 | 9 |
| 3 | 64 |
| 4 | 423 |
| 5 | 2716 |
| 6 | 17199 |
| 7 | 108004 |
| 8 | 673983 |
| 9 | 4183516 |
| 10 | 25845039 |
| 11 | 158993044 |
| 12 | 974443743 |
| 13 | 5952752716 |
| 14 | 36262150479 |
| 15 | 220363399684 |
| 16 | 1336386968703 |
| 17 | 8090385360316 |
| 18 | 48906795729519 |
| 19 | 295279984663924 |
| 20 | 1780943516632863 |