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 | 0 |
| 1 | 1 |
| 2 | 31 |
| 3 | 242 |
| 4 | 3093 |
| 5 | 32525 |
| 6 | 368168 |
| 7 | 4051333 |
| 8 | 45064131 |
| 9 | 499200274 |
| 10 | 5538624025 |
| 11 | 61414079849 |
| 12 | 681135796944 |
| 13 | 7553728681433 |
| 14 | 83772910243607 |
| 15 | 929052526388050 |
| 16 | 10303364319347757 |
| 17 | 114266002348885717 |
| 18 | 1267229634537217144 |
| 19 | 14053790947047408701 |
| 20 | 155858934437282250075 |