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 | 5 |
| 3 | 44 |
| 4 | 590 |
| 5 | 11094 |
| 6 | 276924 |
| 7 | 8821056 |
| 8 | 347992560 |
| 9 | 16608856176 |
| 10 | 941180477760 |
| 11 | 62356907861280 |
| 12 | 4768658639919360 |
| 13 | 416372600735314560 |
| 14 | 41123273761815517440 |
| 15 | 4557176483095745510400 |
| 16 | 562635159090115071744000 |
| 17 | 76906191809174747446425600 |
| 18 | 11573912988161070649533849600 |