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 | 1 |
| 1 | 257 |
| 2 | 6817 |
| 3 | 72097 |
| 4 | 456161 |
| 5 | 2070241 |
| 6 | 7444417 |
| 7 | 22542017 |
| 8 | 59823937 |
| 9 | 143046721 |
| 10 | 314358881 |
| 11 | 644340577 |
| 12 | 1245712417 |
| 13 | 2291519777 |
| 14 | 4038679681 |
| 15 | 6857857921 |
| 16 | 11270724737 |
| 17 | 17995718017 |
| 18 | 28003523617 |
| 19 | 42583563041 |