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 | 2 |
| 2 | 10 |
| 3 | 80 |
| 4 | 838 |
| 5 | 10952 |
| 6 | 171910 |
| 7 | 3148280 |
| 8 | 65890198 |
| 9 | 1551389192 |
| 10 | 40586247910 |
| 11 | 1167964662680 |
| 12 | 36666464437558 |
| 13 | 1247011549249832 |
| 14 | 45672691012357510 |
| 15 | 1792280373542404280 |
| 16 | 75021202465129000918 |
| 17 | 3336499249170658956872 |
| 18 | 157116438405334017308710 |
| 19 | 7809681380575733223237080 |
| 20 | 408621675981135189773468278 |