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 | 1 |
| 2 | 7 |
| 3 | 140 |
| 4 | 5254 |
| 5 | 318854 |
| 6 | 28455182 |
| 7 | 3506576856 |
| 8 | 570360248856 |
| 9 | 118356589567440 |
| 10 | 30512901324706608 |
| 11 | 9566812017770347152 |
| 12 | 3584662956711860108352 |
| 13 | 1581905384865801328253712 |
| 14 | 812047187127758913474118032 |
| 15 | 479763784808095613489811245568 |