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 | 5 |
| 2 | 35 |
| 3 | 189 |
| 4 | 924 |
| 5 | 4290 |
| 6 | 19305 |
| 7 | 85085 |
| 8 | 369512 |
| 9 | 1587222 |
| 10 | 6760390 |
| 11 | 28601650 |
| 12 | 120349800 |
| 13 | 504131940 |
| 14 | 2103781365 |
| 15 | 8751023325 |
| 16 | 36300541200 |
| 17 | 150217371150 |
| 18 | 620309379690 |
| 19 | 2556724903590 |
| 20 | 10520494818600 |
| 21 | 43225511319900 |
| 22 | 177361820257050 |
| 23 | 726860987017074 |
| 24 | 2975511197688624 |
| 25 | 12168371410300700 |