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 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 74 |
| 5 | 360 |
| 6 | 1840 |
| 7 | 9698 |
| 8 | 52409 |
| 9 | 288697 |
| 10 | 1615275 |
| 11 | 9153850 |
| 12 | 52434770 |
| 13 | 303104532 |
| 14 | 1765920785 |
| 15 | 10358843904 |
| 16 | 61129390652 |
| 17 | 362650003202 |
| 18 | 2161590275029 |
| 19 | 12938838382316 |
| 20 | 77745063802045 |
| 21 | 468760264760369 |
| 22 | 2835272729215565 |
| 23 | 17198394229862818 |
| 24 | 104598950726341920 |
| 25 | 637709136315071504 |