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 | 3 |
| 2 | 7 |
| 3 | 18 |
| 4 | 58 |
| 5 | 230 |
| 6 | 1050 |
| 7 | 5277 |
| 8 | 28613 |
| 9 | 165895 |
| 10 | 1023073 |
| 11 | 6682569 |
| 12 | 46054782 |
| 13 | 333712277 |
| 14 | 2534298321 |
| 15 | 20114189445 |
| 16 | 166423322294 |
| 17 | 1432251611705 |
| 18 | 12795182247109 |
| 19 | 118443504257081 |
| 20 | 1134237257303476 |
| 21 | 11219647646806519 |