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 | 21 |
| 2 | 129 |
| 3 | 993 |
| 4 | 7604 |
| 5 | 56955 |
| 6 | 431844 |
| 7 | 3261576 |
| 8 | 24650278 |
| 9 | 186318117 |
| 10 | 1408100748 |
| 11 | 10642345790 |
| 12 | 80432918689 |
| 13 | 607898868394 |
| 14 | 4594402941159 |
| 15 | 34723747771300 |
| 16 | 262436478814437 |
| 17 | 1983452417015597 |
| 18 | 14990612333683132 |
| 19 | 113296622100170154 |