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 | 1 |
| 3 | 15 |
| 4 | 528 |
| 5 | 3990 |
| 6 | 232305 |
| 7 | 4262895 |
| 8 | 128928632 |
| 9 | 1420184304 |
| 10 | 186936865290 |
| 11 | 2416826727315 |
| 12 | 436683783190248 |
| 13 | 6495589851083190 |
| 14 | 102988034105173217 |
| 15 | 3468347338313592735 |
| 16 | 1050976389766688264880 |
| 17 | 19771777981152440202960 |
| 18 | 7439086137698489458667340 |
| 19 | 154685313008524836907739370 |
| 20 | 3369940174123349111629009120 |