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 | 15 |
| 2 | 140 |
| 3 | 1045 |
| 4 | 6835 |
| 5 | 40963 |
| 6 | 230720 |
| 7 | 1240740 |
| 8 | 6437890 |
| 9 | 32468470 |
| 10 | 160010280 |
| 11 | 773624615 |
| 12 | 3680728375 |
| 13 | 17274086235 |
| 14 | 80119845080 |
| 15 | 367821324040 |
| 16 | 1673528845710 |
| 17 | 7554110698850 |
| 18 | 33858536700040 |
| 19 | 150802994850570 |