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) |
|---|---|
| 2 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 19 |
| 6 | 203 |
| 7 | 4343 |
| 8 | 63853 |
| 9 | 58129 |
| 10 | 160127 |
| 11 | 8885501 |
| 12 | 1500518539 |
| 13 | 404156337271 |
| 14 | 16040576541971 |
| 15 | 1694200740145637 |
| 16 | 24047240650458731 |
| 17 | 22823917472900053 |
| 18 | 2511014355032164231 |
| 19 | 143734030512459889193 |
| 20 | 49611557898193759558813 |
| 21 | 950601970122346247310883 |