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 | 1 |
| 2 | 5 |
| 3 | 32 |
| 4 | 228 |
| 5 | 1675 |
| 6 | 12368 |
| 7 | 91381 |
| 8 | 675215 |
| 9 | 4989192 |
| 10 | 36865413 |
| 11 | 272400601 |
| 12 | 2012783316 |
| 13 | 14872568832 |
| 14 | 109894245430 |
| 15 | 812014744423 |
| 16 | 6000022499694 |
| 17 | 44334502845081 |
| 18 | 327590128640501 |
| 19 | 2420581837980562 |
| 20 | 17885814992891027 |