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 | 4 |
| 2 | 44 |
| 3 | 440 |
| 4 | 4360 |
| 5 | 43164 |
| 6 | 427284 |
| 7 | 4229680 |
| 8 | 41869520 |
| 9 | 414465524 |
| 10 | 4102785724 |
| 11 | 40613391720 |
| 12 | 402031131480 |
| 13 | 3979697923084 |
| 14 | 39394948099364 |
| 15 | 389969783070560 |
| 16 | 3860302882606240 |
| 17 | 38213059042991844 |
| 18 | 378270287547312204 |
| 19 | 3744489816430130200 |
| 20 | 37066627876753989800 |